Only highlight actual errors in PPhtml (#1713)

Don't highlight "ERROR" in "TERROR" in a chapter title, for
example.

Fixes #1710

Author: windymilla

src/guiguts/tools/pphtml.py

@@ -110,9 +110,9 @@ def run(self) -> None:
 
         self.dialog.display_entries()
         self.colorize_errors(PPhtmlChecker.fail_flag, HighlightTag.CHECKER_ERROR_PREFIX)
-        self.colorize_errors("ERROR", HighlightTag.CHECKER_ERROR_PREFIX)
+        self.colorize_errors("ERROR: ", HighlightTag.CHECKER_ERROR_PREFIX)
         self.colorize_errors(PPhtmlChecker.warn_flag, HighlightTag.CHECKER_WARNING)
-        self.colorize_errors("WARNING", HighlightTag.CHECKER_WARNING)
+        self.colorize_errors("WARNING: ", HighlightTag.CHECKER_WARNING)
         # Select first entry (which might not be one with a line number)
         self.dialog.select_entry_by_index(0)