Match count in status bar

[redsti-github]

From #4030

Adds the $(matches) option to the status bar, which displays the total number of matches (and current match) found while using the Find, FindNext and FindPrevious actions.

Displays as [X/Y] when searching and [Y matches] after performing any action.

Currently limits the number of matches to 1000 for performance reasons.

[redsti-github]

TODO:

• make the maximum match count an editable setting, rather than just 1000
• for performance, we could cache the found matches, and if the next action is FindNext or FindPrevious we can use the cache and not search the entire file again
• when placing the cursor back on a match, show [X/Y]
• update the docs/help pages