git-review-rebase: fix coloring of different token on the left side.

The original code had a workaround to avoid highlighting all the spaces
from the last character on the left side, but it was a bit too eager
depending on the lexer used, for example with the Make lexer we wouldn't
get two tokens, one for spaces and one for the newline.

Instead, stop on the previous but last token only if it's only
spaces/newlines.

This doesn't change the highlighting for C source code but allows the
highlighting on the left side of a Make diff.

Signed-off-by: Quentin Casasnovas <quentin.casasnovas@vates.tech>

Author: casasnovas

scripts/git-review-rebase/src/git_review_rebase/ui/diff_table.py

@@ -95,7 +95,9 @@ def highlight_diff_tokens(self, left_text: Text, middle_text: Text, right_text:
                 continue
 
             for i in range(l1, l2):
-                if i == len(left_tokens) - 1 or i == len(left_tokens) - 2:
+                if i == len(left_tokens) - 1 or (
+                    i == len(left_tokens) - 2 and not left_tokens[i].strip()
+                ):
                     break
                 left_text.stylize(bg, left_idx + 1, left_idx + len(left_tokens[i]) + 1)
                 left_idx += len(left_tokens[i])