Wayland: Fix some keys not repeating

According to the libxkbcommon documentation[1], xkb_keymap_key_repeats
requires keymap and keycode as input:

int xkb_keymap_key_repeats( struct xkb_keymap * keymap,
			    xkb_keycode_t key)

However, in inputChar in wl_input.c we are passing in xkb_keysym_t,
which was a type mismatch.

This results in some keys not repeating when they should and vice versa.

[1] https://xkbcommon.org/doc/current/group__components.html#ga9d7f998efeca98b3afc7c257bbac90a8

Closes #1908.

(cherry picked from commit 216d5e8402)

src/wl_init.c

@@ -560,7 +560,7 @@ static GLFWbool inputChar(_GLFWwindow* window, uint32_t key)
         }
     }
 
-    return xkb_keymap_key_repeats(_glfw.wl.xkb.keymap, syms[0]);
+    return xkb_keymap_key_repeats(_glfw.wl.xkb.keymap, code);
 }
 
 static void keyboardHandleKey(void* data,