Car docs diff bot: auto-generate column header (#25622)

* Fix bot

* test

* Revert "test"

This reverts commit ba4a67cd8c88f8b7e082fb1fad5a1e10b51012ab.

selfdrive/debug/print_docs_diff.py

@@ -10,7 +10,7 @@ from selfdrive.car.docs_definitions import Column
 FOOTNOTE_TAG = "<sup>{}</sup>"
 STAR_ICON = '<a href="##"><img valign="top" src="https://raw.githubusercontent.com/commaai/openpilot/master/docs/assets/icon-star-{}.svg" width="22" /></a>'
 COLUMNS = "|" + "|".join([column.value for column in Column]) + "|"
-COLUMN_HEADER = "|---|---|---|:---:|:---:|:---:|:---:|"
+COLUMN_HEADER = "|---|---|---|{}|".format("|".join([":---:"] * (len(Column) - 3)))
 ARROW_SYMBOL = "➡️"