refactor(punctuation): remove orphan code for handling lone punctuation

The case of lone punctuation is already handled at the top of restore(). The
removed if statement would never be called and would in fact raise an
AttributeError because the _punc_index named tuple doesn't have the attribute
`mark`.

TTS/tts/utils/text/punctuation.py

@@ -15,7 +15,6 @@ class PuncPosition(Enum):
     BEGIN = 0
     END = 1
     MIDDLE = 2
-    ALONE = 3
 
 
 class Punctuation:
@@ -92,7 +91,7 @@ class Punctuation:
             return [text], []
         # the text is only punctuations
         if len(matches) == 1 and matches[0].group() == text:
-            return [], [_PUNC_IDX(text, PuncPosition.ALONE)]
+            return [], [_PUNC_IDX(text, PuncPosition.BEGIN)]
         # build a punctuation map to be used later to restore punctuations
         puncs = []
         for match in matches:
@@ -147,9 +146,6 @@ class Punctuation:
         if current.position == PuncPosition.END:
             return [text[0] + current.punc] + cls._restore(text[1:], puncs[1:], num + 1)
 
-        if current.position == PuncPosition.ALONE:
-            return [current.mark] + cls._restore(text, puncs[1:], num + 1)
-
         # POSITION == MIDDLE
         if len(text) == 1:  # pragma: nocover
             # a corner case where the final part of an intermediate

tests/text_tests/test_punctuation.py

@@ -11,6 +11,8 @@ class PunctuationTest(unittest.TestCase):
             ("This, is my text ... to be striped !! from text", "This is my text to be striped from text"),
             ("This, is my text ... to be striped  from text?", "This is my text to be striped  from text"),
             ("This, is my text to be striped from text", "This is my text to be striped from text"),
+            (".", ""),
+            (" . ", ""),
         ]
 
     def test_get_set_puncs(self):