Separate category value from notes in results list

Only works if there is no search or the match is close enough for the
result text to include the category value.

src/calibre/gui2/library/notes.py

@@ -34,7 +34,7 @@ class NotesResultsDelegate(ResultsDelegate):
     def result_data(self, result):
         if not isinstance(result, dict):
             return None, None, None, None, None
-        full_text = result['text']
+        full_text = result['text'].replace('\n', ': ', 1)
         parts = full_text.split('\x1d', 2)
         before = after = ''
         if len(parts) > 2:
@@ -44,6 +44,8 @@ class NotesResultsDelegate(ResultsDelegate):
             before, text = parts
         else:
             text = parts[0]
+        if len(parts) > 1 and before:
+            before = before.replace('\n', ': ', 1)
         return False, before, text, after, False
 
 
@@ -519,4 +521,5 @@ if __name__ == '__main__':
     br = NotesBrowser()
     br.exec()
     del br
+
     del app