Fix crash with almost empty docstrings

Author: DanielNoord

pydocstringformatter/_formatting/formatters_default.py

@@ -152,6 +152,9 @@ def treat_summary(
         description_exists: bool,
     ) -> str:
         """Add a period to the end of single-line docstrings and summaries."""
+        if not summary:
+            return summary
+
         if summary[-1] in self.END_OF_SENTENCE_PUNCTUATION:
             return summary
 

pydocstringformatter/_formatting/formatters_pep257.py

@@ -38,6 +38,9 @@ def treat_summary(
         """Split a summary and body if there is a period after the summary."""
         new_summary = None
 
+        if not summary:
+            return summary
+
         if _utils.is_rst_title(summary):
             return summary
 

tests/data/format/summary_splitter/regression_151.py

@@ -0,0 +1,2 @@
+class GithubIssue151:
+    """ """

tests/data/format/summary_splitter/regression_151.py.out

@@ -0,0 +1,2 @@
+class GithubIssue151:
+    """"""