wezterm: Added toggling ability for leader key

Sometimes the leader key gets in the way. Since my leader key
combination is C-a by default, this interferes with the (rare) times
that I want to increment something in vim (also C-a).

So, this commit allows toggling the leader key in wezterm off, so it
passes through to the actual applications. You can toggle it with
`C-Alt-a`.

Commit made possible with the help of the comments in this issue:
https://github.com/wez/wezterm/issues/656

wezterm/.config/wezterm/events.lua

@@ -58,6 +58,20 @@ local function setup()
         wezterm.sleep_ms(1000)
         os.remove(name)
     end)
+
+    wezterm.on("toggle-leader", function(window, pane)
+        wezterm.log_info("toggling the leader")
+        local overrides = window:get_config_overrides() or {}
+        if not overrides.leader then
+            wezterm.log_info("leader wasn't set")
+            overrides.leader = { key = "s", mods = "SUPER" };
+        else
+            wezterm.log_info("leader was set")
+            overrides.leader = nil
+        end
+
+        window:set_config_overrides(overrides)
+    end)
 end
 
 return { setup = setup }

wezterm/.config/wezterm/maps.lua

@@ -73,7 +73,8 @@ local keys = {
         key = 'l',
         mods = 'LEADER',
         action = act.EmitEvent 'ActivatePaneDirection-Right'
-    }
+    },
+    { key = 'a', mods = 'CTRL|ALT', action = act.EmitEvent 'toggle-leader'}
 
 }
 -- Leader + number to activate that tab
@@ -108,6 +109,6 @@ local key_tables = {
         { key = 'g', mods = 'CTRL', action = act.ScrollToTop },
         { key = 'G', mods = 'CTRL', action = act.ScrollToBottom },
         { key = 'Escape', action = 'PopKeyTable' }
-    }
+    },
 }
 return { keys = keys, key_tables = key_tables }