wayland: fix --no-overlap meaning and behavior

As I understand "no overlap", it means "do not overlap". This
correspond to this call from the Wayland backend:

zwlr_layer_surface_v1_set_exclusive_zone(..., overlap ? -1 : 0);

The spec says:

> If set to zero, the surface indicates that it would like to be moved
> to avoid occluding surfaces with a positive exclusive zone. If set to
> -1, the surface indicates that it would not like to be moved to
> accommodate for other surfaces, and the compositor should extend it
> all the way to the edges it is anchored to.

So "0" is "do not overlap", and "-1" is "overlap", okay.

The problem is that the overlap boolean comes from !client->no_overlap.
Meaning that -n => true => !true => false so -n gives 0 "do not overlap"

I think the code is correct, but the description of the argument is
miss-leading.

Also, we initiate the menu->overlap sooner, because the renderer need
this to gather the maximum available geometry correctly. I'm not sure
if this the best way to to so.

Author: stacyharper

client/common/common.c

@@ -561,7 +561,7 @@ struct bm_menu*
 menu_with_options(struct client *client)
 {
     struct bm_menu *menu;
-    if (!(menu = bm_menu_new(NULL)))
+    if (!(menu = bm_menu_new(NULL, !client->no_overlap)))
         return NULL;
 
     if (client->vim_init_mode_normal) {

lib/bemenu.h

@@ -401,7 +401,7 @@ enum bm_key_binding {
  * @param renderer Name of renderer to be used for this instance, pass **NULL** for auto-detection.
  * @return bm_menu for new menu instance, **NULL** if creation failed.
  */
-BM_PUBLIC struct bm_menu* bm_menu_new(const char *renderer);
+BM_PUBLIC struct bm_menu* bm_menu_new(const char *renderer, bool overlap);
 
 /**
  * Release bm_menu instance.

lib/menu.c

@@ -47,7 +47,7 @@ static struct bm_item** (*filter_func[BM_FILTER_MODE_LAST])(struct bm_menu *menu
 };
 
 struct bm_menu*
-bm_menu_new(const char *renderer)
+bm_menu_new(const char *renderer, bool overlap)
 {
     struct bm_menu *menu;
     if (!(menu = calloc(1, sizeof(struct bm_menu))))
@@ -58,6 +58,7 @@ bm_menu_new(const char *renderer)
     menu->key_binding = BM_KEY_BINDING_DEFAULT;
     menu->vim_mode = 'i';
     menu->vim_last_key = 0;
+    menu->overlap = overlap;
 
     uint32_t count;
     const struct bm_renderer **renderers = bm_get_renderers(&count);

man/bemenu.1.scd.in

@@ -168,7 +168,7 @@ These options are only available on backends specified in the parentheses:
 	should appear on all monitors.
 
 *-n, --no-overlap* (Wayland)
-	Set the *bemenu* window to be on top of any other panels.
+	Make the *bemenu* window to not overlap any other panels.
 
 *-M, --margin* <_margin_> (Wayland, X11)
 	Specify the _margin_ (empty space) in pixels to leave between menu and