[clang-format] Ensure dump_format_style.py can generate ClangFormatStyleOptions.rst without manual intervention

[MyDeveloperDay]

Summary

This revision is the last in a series of revisions to return clang/doc/tools/dump_format_style.py to be being able to parse Format.h without needing to manually merge the ClangFormatStyleOptions.rst file.

The final modification to dump_format_style.py is needed following the addition of a nested enumeration inside a nested structure following the introduction of D68296: [clang-format] Add ability to wrap braces after multi-line control statements

Prior related revisions will allow for a fully clang-formatted clang/include/clang/Format/Format.h to once again be used at the source.
D69951: [clang-format] NFC allow Format.h to be clang-formatted but still maintain the same doc layout in ClangFormatStyleOptions.rst
D69433: [clang-format] [NFC] update the documentation in Format.h to allow dump_format_style.py to get a little closer to being correct. (part 2)
D69404: [clang-format] [NFC] update the documentation in Format.h to allow dump_format_style.py to get a little closer to being correct.

[MyDeveloperDay]

Just in case you want proof the generated html looks the same:

[mitchell-stellar]

LGTM

clang/docs/ClangFormatStyleOptions.rst

* ``BWACS_Always`` (in configuration: ``Always``)
 
         if (foo())
         {
         } else
         {}
         for (int i = 0; i < 10; ++i)
         {}
 
+
   * ``bool AfterEnum`` Wrap enum definitions.
 
     .. code-block:: c++
 
       true:
       enum X : int
       {
         B

clang/docs/tools/dump_format_style.py

class Enum(object):
   def __init__(self, name, comment):
     self.name = name
     self.comment = comment.strip()
     self.values = []
 
   def __str__(self):
     return '\n'.join(map(str, self.values))
 
+class NestedEnum(object):
+  def __init__(self, name, enumtype, comment, values):
+    self.name = name
+    self.comment = comment
+    self.values = values
+    self.type = enumtype
+
+  def __str__(self):
+    s = '\n* ``%s %s``\n%s' % (self.type, self.name,
+                                 doxygen2rst(indent(self.comment, 2)))
+    s += indent('\nPossible values:\n\n', 2)
+    s += indent('\n'.join(map(str, self.values)),2)
+    return s;
+
 class EnumValue(object):
   def __init__(self, name, comment, config):
     self.name = name
     self.comment = comment
     self.config = config
 
   def __str__(self):
     return '* ``%s`` (in configuration: ``%s``)\n%s' % (
elif state == State.InNestedStruct:
       elif line == '};':
         state = State.InStruct
         nested_structs[nested_struct.name] = nested_struct
     elif state == State.InNestedFieldComent:
       if line.startswith('///'):
         comment += clean_comment_line(line)
       else:
         state = State.InNestedStruct
-        nested_struct.values.append(NestedField(line.replace(';', ''), comment))
+        field_type, field_name = re.match(r'([<>:\w(,\s)]+)\s+(\w+);',line).groups()
+        if field_type in enums:
+            nested_struct.values.append(NestedEnum(field_name,field_type,comment,enums[field_type].values))
+        else:
+            nested_struct.values.append(NestedField(field_type + " " + field_name, comment))
+
     elif state == State.InEnum:
       if line.startswith('///'):
         state = State.InEnumMemberComment
         comment = clean_comment_line(line)
       elif line == '};':
         state = State.InStruct
         enums[enum.name] = enum
       else: