[clang-tidy] fix pr docs comments

Author: vbvictor

clang-tools-extra/docs/clang-tidy/checks/misc/const-correctness.rst

@@ -197,11 +197,12 @@ Options
     int *changing_pointee = &value;
     changing_pointee = &result;
 
-.. option:: AllowedTypes (default = '')
+.. option:: AllowedTypes
 
   A semicolon-separated list of names of types that will be excluded from
   const-correctness checking. Regular expressions are accepted, e.g.
   `[Rr]ef(erence)?$` matches every type with suffix `Ref`, `ref`, `Reference`
   and `reference`. If a name in the list contains the sequence `::`, it is
   matched against the qualified type name (i.e. ``namespace::Type``),
   otherwise it is matched against only the type name (i.e. ``Type``).
+  Default is empty.