feat(builtin): implement filter for keymaps (#2462)

lua/telescope/builtin/__internal.lua

@@ -1129,7 +1129,6 @@ internal.registers = function(opts)
     :find()
 end
 
--- TODO: make filtering include the mapping and the action
 internal.keymaps = function(opts)
   opts.modes = vim.F.if_nil(opts.modes, { "n", "i", "c", "x" })
   opts.show_plug = vim.F.if_nil(opts.show_plug, true)
@@ -1148,6 +1147,7 @@ internal.keymaps = function(opts)
         if
           (opts.show_plug or not string.find(keymap.lhs, "<Plug>"))
           and (not opts.lhs_filter or opts.lhs_filter(keymap.lhs))
+          and (not opts.filter or opts.filter(keymap))
         then
           table.insert(keymaps_table, keymap)
           max_len_lhs = math.max(max_len_lhs, #utils.display_termcodes(keymap.lhs))