fix: correctly capitalize suffix acronyms written with dots (closes #141)

lc() strips only trailing periods, so 'M.D.' became 'm.d' which failed
to match the dot-free exception key 'md'. Now also try the dot-stripped
form when looking up capitalization exceptions.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: derek73

nameparser/parser.py

@@ -962,6 +962,8 @@ def cap_word(self, word: str, attribute: HumanNameAttributeT) -> str:
         exceptions = self.C.capitalization_exceptions
         if lc(word) in exceptions:
             return exceptions[lc(word)]
+        if lc(word).replace('.', '') in exceptions:
+            return exceptions[lc(word).replace('.', '')]
         mac_match = self.C.regexes.mac.match(word)
         if mac_match:
             def cap_after_mac(m: re.Match) -> str:

tests/test_capitalization.py

@@ -93,6 +93,13 @@ def test_capitalize_multiple_suffixes_still_split_correctly(self) -> None:
         hn.capitalize()
         self.assertEqual(hn.suffix_list, ['Ph.D.', 'M.D.'])
 
+    def test_capitalize_suffix_acronym_with_dots(self) -> None:
+        # Suffixes already written with dots (e.g. "M.D.") should capitalize
+        # to their exception form, not title-case to "M.d." (issue #141)
+        hn = HumanName('GREGORY HOUSE M.D.')
+        hn.capitalize()
+        self.assertEqual(hn.suffix, 'M.D.')
+
     # Leaving already-capitalized names alone
     def test_no_change_to_mixed_chase(self) -> None:
         hn = HumanName('Shirley Maclaine')