[doc] Fix hugo ignoreFiles

Entries are regex, not glob. Switch some uses of '*' to '.*' so they
work as intended.

Signed-off-by: Greg Chadwick <gac@lowrisc.org>
diff --git a/site/docs/config.toml b/site/docs/config.toml
index 42249af..2e6adc4 100644
--- a/site/docs/config.toml
+++ b/site/docs/config.toml
@@ -45,15 +45,15 @@
   ".*\\.xdc$",
   ".*\\.yml$",
   ".*\\.clang-format$",
-  "/__pycache__/*",
-  "/build/*",
+  "/__pycache__/.*",
+  "/build/.*",
   "/ci/",
-  "/hw/vendor/*",
-  "/sw/vendor/*",
+  "/hw/vendor/.*",
+  "/sw/vendor/.*",
   "/meson.build$",
   "/opentitan-docs/",
   "/scratch/",
-  "/site/*",
+  "/site/.*",
   "/util/doxygen/",
   ".*/jgproject/.*",
   ".*/verdiLog/.*",