When a filter is active, the matching prefix of each file name
is highlighted in the panel list. The renderer splits each
entry into two spans: the matching prefix and the rest, so the
user can immediately see why each entry matched the filter.
- Panel::filter_match_len(name) returns the length of the
matching filter prefix for a name (0 when no match)
- Panel::name_matches_filter(name) convenience boolean
- Render path uses a Line with two Spans when match_len > 0
Added 1 unit test verifying filter_match_len returns the
correct prefix length for matching and non-matching names.
Tests: 1405 pass (was 1403), zero warnings.
vasilito
78ff5b5c4c