[hlsearch] add note about two-attribute highlight model #2861

Traced through code and confirmed clear_search() always wipes both
scopes before setting a new pattern, so the or in drawRow never
chooses between two live patterns. Left a comment for future readers.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: saulbert

visidata/features/hlsearch.py

@@ -3,6 +3,12 @@
 import re
 
 
+# NOTE: both Sheet and Column have highlight_regex, but g/ sets per-column
+# (not sheet-level), so sheet.highlight_regex is only used by highlight-sheet.
+# clear_search() always wipes both before any new pattern is set, so the
+# `col.highlight_regex or sheet.highlight_regex` in drawRow() never chooses
+# between two live patterns. The two-attribute model seems like it could be simplified to
+# one.  See PR #2861 for discussion.
 TableSheet.init('highlight_regex', lambda: None, copy=False)
 Column.init('highlight_regex', lambda: None, copy=False)