Touch up Python build instructions. (#11424)

* Our `PYTHONPATH` docs had some references to old paths
(`compiler-api\python_package`) still in there. Windows instructions now
use `.env.bat`, matching the `source .env && export PYTHONPATH`
instructions on Linux.
* Added Python 3.10 to the classifiers that will appear on
https://pypi.org/project/iree-compiler/
* The `iree_benchmark_module` script was missing from one build target -
this was working in some configurations but not all
* Removed a duplicate instruction to install from
`build_requirements.txt` (it was a "prerequisite" and an explicit step)
* Added a recommendation to consider using `py` on Windows instead of
`python`
(https://docs.python.org/3/using/windows.html#python-launcher-for-windows)
diff --git a/.gitignore b/.gitignore
index 977d265..0409f07 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,10 +1,10 @@
 # Python
+.env
 *.pyc
 **/.ipynb_checkpoints/
 .pytype/
 
 # Visual Studio files
-.env
 .vs/
 .vscode/
 *.sdf
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 566872e..4ecf827 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -850,14 +850,13 @@
 if(IREE_BUILD_PYTHON_BINDINGS)
   # Write out a .env file to make IDEs and developers happy.
   # Yes, we are writing this to the source dir. It is only for IDEs and if
-  # it gets clobbered, it is fine.
+  # it gets clobbered, it is fine (it is also ignored in .gitignore).
   set(_PYTHONPATH_ENV "PYTHONPATH=$<SHELL_PATH:${CMAKE_CURRENT_BINARY_DIR}/compiler/bindings/python;${CMAKE_CURRENT_BINARY_DIR}/runtime/bindings/python>\n")
-  file(GENERATE OUTPUT "${CMAKE_CURRENT_SOURCE_DIR}/.env"
-    CONTENT "${_PYTHONPATH_ENV}"
-  )
-  file(GENERATE OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/.env"
-    CONTENT "${_PYTHONPATH_ENV}"
-  )
+  file(GENERATE OUTPUT "${CMAKE_CURRENT_SOURCE_DIR}/.env" CONTENT "${_PYTHONPATH_ENV}")
+  file(GENERATE OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/.env" CONTENT "${_PYTHONPATH_ENV}")
+  # Similarly, write out .env.bat for Windows.
+  set(_PYTHONPATH_ENV_BAT "set PYTHONPATH=$<SHELL_PATH:${CMAKE_CURRENT_BINARY_DIR}/compiler/bindings/python;${CMAKE_CURRENT_BINARY_DIR}/runtime/bindings/python>\n")
+  file(GENERATE OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/.env.bat" CONTENT "${_PYTHONPATH_ENV_BAT}")
 endif()
 
 if(IREE_BUILD_BINDINGS_TFLITE)
diff --git a/compiler/setup.py b/compiler/setup.py
index 9866c57..e60b803 100644
--- a/compiler/setup.py
+++ b/compiler/setup.py
@@ -234,6 +234,7 @@
         "-DPython3_EXECUTABLE={}".format(sys.executable),
         "-DCMAKE_BUILD_TYPE={}".format(cfg),
         get_env_cmake_option("IREE_TARGET_BACKEND_CUDA"),
+        # TODO(scotttodd): include IREE_TARGET_BACKEND_WEBGPU here (and in env)
         get_env_cmake_option("IREE_ENABLE_CPUINFO", "ON"),
     ]
 
@@ -383,9 +384,11 @@
     classifiers=[
         "Development Status :: 3 - Alpha",
         "License :: OSI Approved :: Apache Software License",
+        "Programming Language :: Python :: 3",
         "Programming Language :: Python :: 3.7",
         "Programming Language :: Python :: 3.8",
         "Programming Language :: Python :: 3.9",
+        "Programming Language :: Python :: 3.10",
     ],
     ext_modules=[
         CMakeExtension("iree.compiler._mlir_libs._mlir"),
diff --git a/docs/website/docs/building-from-source/python-bindings-and-importers.md b/docs/website/docs/building-from-source/python-bindings-and-importers.md
index c48d374..d2c3367 100644
--- a/docs/website/docs/building-from-source/python-bindings-and-importers.md
+++ b/docs/website/docs/building-from-source/python-bindings-and-importers.md
@@ -27,8 +27,6 @@
 
 * A relatively recent Python3 installation >=3.7 (we aim to support
   [non-eol Python versions](https://endoflife.date/python)).
-* Installation of python dependencies as specified in
-  [`runtime/bindings/python/iree/runtime/build_requirements.txt`](https://github.com/iree-org/iree/blob/main/runtime/bindings/python/iree/runtime/build_requirements.txt).
 
 **CMake Variables:**
 
@@ -79,6 +77,13 @@
 === "Windows"
 
     ``` powershell
+    # Make sure your 'python' is what you expect.
+    # Also consider using the Python launcher 'py' instead of 'python':
+    # https://docs.python.org/3/using/windows.html#python-launcher-for-windows
+    which python
+    python --version
+    py --list-paths
+
     # Create a persistent virtual environment (first time only).
     python -m venv .venv
 
@@ -112,8 +117,7 @@
         .
     cmake --build .
 
-    # Add ./bindings/python and compiler-api/python_package to PYTHONPATH and
-    # use the API.
+    # Add the bindings/python paths to PYTHONPATH and use the API.
     source .env && export PYTHONPATH
     python -c "import iree.compiler"
     python -c "import iree.runtime"
@@ -125,9 +129,8 @@
     cmake -GNinja -DCMAKE_BUILD_TYPE=RelWithDebInfo -DIREE_BUILD_PYTHON_BINDINGS=ON .
     cmake --build .
 
-    # Add bindings\python and compiler-api\python_package to PYTHONPATH and use
-    # the API.
-    set PYTHONPATH="$pwd\compiler-api\python_package;$pwd\bindings\python;%PYTHONPATH%"
+    # Add the bindings/python paths to PYTHONPATH and use the API.
+    .env.bat
     python -c "import iree.compiler"
     python -c "import iree.runtime"
     ```
diff --git a/integrations/tensorflow/python_projects/iree_tf/setup.py b/integrations/tensorflow/python_projects/iree_tf/setup.py
index 3a33691..103bf0d 100644
--- a/integrations/tensorflow/python_projects/iree_tf/setup.py
+++ b/integrations/tensorflow/python_projects/iree_tf/setup.py
@@ -94,6 +94,10 @@
         "Development Status :: 3 - Alpha",
         "License :: OSI Approved :: Apache Software License",
         "Programming Language :: Python :: 3",
+        "Programming Language :: Python :: 3.7",
+        "Programming Language :: Python :: 3.8",
+        "Programming Language :: Python :: 3.9",
+        "Programming Language :: Python :: 3.10",
     ],
     python_requires=">=3.7",
     packages=find_namespace_packages(include=[
diff --git a/integrations/tensorflow/python_projects/iree_tflite/setup.py b/integrations/tensorflow/python_projects/iree_tflite/setup.py
index 3173ad7..19d0f14 100644
--- a/integrations/tensorflow/python_projects/iree_tflite/setup.py
+++ b/integrations/tensorflow/python_projects/iree_tflite/setup.py
@@ -94,6 +94,10 @@
         "Development Status :: 3 - Alpha",
         "License :: OSI Approved :: Apache Software License",
         "Programming Language :: Python :: 3",
+        "Programming Language :: Python :: 3.7",
+        "Programming Language :: Python :: 3.8",
+        "Programming Language :: Python :: 3.9",
+        "Programming Language :: Python :: 3.10",
     ],
     python_requires=">=3.7",
     packages=find_namespace_packages(include=[
diff --git a/integrations/tensorflow/python_projects/iree_xla/setup.py b/integrations/tensorflow/python_projects/iree_xla/setup.py
index 22a1a8d..61e1892 100644
--- a/integrations/tensorflow/python_projects/iree_xla/setup.py
+++ b/integrations/tensorflow/python_projects/iree_xla/setup.py
@@ -94,6 +94,10 @@
         "Development Status :: 3 - Alpha",
         "License :: OSI Approved :: Apache Software License",
         "Programming Language :: Python :: 3",
+        "Programming Language :: Python :: 3.7",
+        "Programming Language :: Python :: 3.8",
+        "Programming Language :: Python :: 3.9",
+        "Programming Language :: Python :: 3.10",
     ],
     python_requires=">=3.7",
     packages=find_namespace_packages(include=[
diff --git a/runtime/bindings/python/CMakeLists.txt b/runtime/bindings/python/CMakeLists.txt
index 09806b6..24034af 100644
--- a/runtime/bindings/python/CMakeLists.txt
+++ b/runtime/bindings/python/CMakeLists.txt
@@ -71,6 +71,7 @@
     "iree/runtime/system_setup.py"
     "iree/runtime/tracing.py"
     "iree/runtime/scripts/iree_benchmark_trace/__main__.py"
+    "iree/runtime/scripts/iree_benchmark_module/__main__.py"
     "iree/runtime/scripts/iree_run_trace/__main__.py"
     "iree/runtime/scripts/iree_run_module/__main__.py"
     ${_PYTHON_EXTRA_SRCS}
diff --git a/runtime/setup.py b/runtime/setup.py
index 7d1879f..8232661 100644
--- a/runtime/setup.py
+++ b/runtime/setup.py
@@ -372,9 +372,11 @@
     classifiers=[
         "Development Status :: 3 - Alpha",
         "License :: OSI Approved :: Apache Software License",
+        "Programming Language :: Python :: 3",
         "Programming Language :: Python :: 3.7",
         "Programming Language :: Python :: 3.8",
         "Programming Language :: Python :: 3.9",
+        "Programming Language :: Python :: 3.10",
     ],
     url="https://github.com/iree-org/iree",
     python_requires=">=3.7",