pw_span: Switch from pw::span to std::span

Replace pw::span with std::span and "pw_span/span.h" with <span>
throughout the codebase.

Change-Id: Ib1fa873168b6093794e861611d750fcad6285d6c
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/12801
Commit-Queue: Wyatt Hepler <hepler@google.com>
Reviewed-by: Rob Mohr <mohrr@google.com>
Reviewed-by: Keir Mierle <keir@google.com>
diff --git a/pw_tokenizer/tokenize.cc b/pw_tokenizer/tokenize.cc
index 4f29876..c7e3699 100644
--- a/pw_tokenizer/tokenize.cc
+++ b/pw_tokenizer/tokenize.cc
@@ -40,11 +40,11 @@
 
   va_list args;
   va_start(args, types);
-  const size_t encoded_bytes =
-      EncodeArgs(types,
-                 args,
-                 span<uint8_t>(static_cast<uint8_t*>(buffer) + sizeof(token),
-                               *buffer_size_bytes - sizeof(token)));
+  const size_t encoded_bytes = EncodeArgs(
+      types,
+      args,
+      std::span<uint8_t>(static_cast<uint8_t*>(buffer) + sizeof(token),
+                         *buffer_size_bytes - sizeof(token)));
   va_end(args);
 
   *buffer_size_bytes = sizeof(token) + encoded_bytes;