chore: Improve document

Apply format for all doxygen documents.
Every document has the following structure.
Signature of the function

@brief description
@params parameters
@pre    preconditions
@returns possible return values
@note	notes
@see-also

Doxyfile

@@ -38,6 +38,7 @@ EXPAND_ONLY_PREDEF     = YES
 # Predefine some macros to clean up the output.
 PREDEFINED             = "XXH_DOXYGEN=" \
                          "XXH_PUBLIC_API=" \
+                         "XXH_NOESCAPE=" \
                          "XXH_FORCE_INLINE=static inline" \
                          "XXH_NO_INLINE=static" \
                          "XXH_RESTRICT=restrict" \

Doxyfile-internal

@@ -38,6 +38,7 @@ EXPAND_ONLY_PREDEF     = YES
 # Predefine some macros to clean up the output.
 PREDEFINED             = "XXH_DOXYGEN=" \
                          "XXH_PUBLIC_API=" \
+                         "XXH_NOESCAPE=" \
                          "XXH_FORCE_INLINE=static inline" \
                          "XXH_NO_INLINE=static" \
                          "XXH_RESTRICT=restrict" \