pw_tokenizer: Update C naming style

- Update C symbols to the module_name_SymbolName style.
- Rename and move the token alias.
- Update pw_metric/metric.h to refer to pw::tokenizer::Token instead of
  uint32_t.

Change-Id: I75c5df8a690b9c29472a8e64c6d82aa4fefca6aa
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/17160
Commit-Queue: Wyatt Hepler <hepler@google.com>
Reviewed-by: Keir Mierle <keir@google.com>
diff --git a/pw_tokenizer/base64.cc b/pw_tokenizer/base64.cc
index 6ce4a4c..3404916 100644
--- a/pw_tokenizer/base64.cc
+++ b/pw_tokenizer/base64.cc
@@ -20,7 +20,7 @@
 
 namespace pw::tokenizer {
 
-extern "C" size_t pw_TokenizerPrefixedBase64Encode(
+extern "C" size_t pw_tokenizer_PrefixedBase64Encode(
     const void* binary_message,
     size_t binary_size_bytes,
     void* output_buffer,
@@ -41,10 +41,10 @@
   return encoded_size;
 }
 
-extern "C" size_t pw_TokenizerPrefixedBase64Decode(const void* base64_message,
-                                                   size_t base64_size_bytes,
-                                                   void* output_buffer,
-                                                   size_t output_buffer_size) {
+extern "C" size_t pw_tokenizer_PrefixedBase64Decode(const void* base64_message,
+                                                    size_t base64_size_bytes,
+                                                    void* output_buffer,
+                                                    size_t output_buffer_size) {
   const char* base64 = static_cast<const char*>(base64_message);
 
   if (base64_size_bytes == 0 || base64[0] != kBase64Prefix) {