add support for regex groups

If a filter regex contains groups, then we only highlight the group matches.

src/ui/bigtext/highlight_regex.py

@@ -64,12 +64,14 @@ class HighlightRegex(Highlight):
         match_iter = re.finditer(self.regex, line.line())
         for match in match_iter:
             # print("%s" % match)
-            start_char = match.start(0)
-            end_char = match.end(0)
-
-            start_column = line.char_to_column(start_char)
-            end_column = line.char_to_column(end_char)
 
+            # if the regex has groups then skip the first, it represents the whole match,
+            # but we only want to highlight the groups
+            first_group = 1 if len(match.groups()) > 0 else 0
+            for i in range(first_group, len(match.groups()) + 1):
+                start_column = line.char_to_column(match.start(i))
+                end_column = line.char_to_column(match.end(i))
+                # print(f"highlight: {start_column}:{end_column} - {match.group(i)}")
                 result.append(HighlightedRange(
                     start_column,
                     end_column - start_column,