config: move parse_keymap to free function

jay-config/src/keyboard/keymap.rs

@@ -9,10 +9,8 @@ impl Keymap {
     pub fn is_invalid(self) -> bool {
         self == Self::INVALID
     }
-
-    pub fn parse(self, keymap: &str) -> Self {
-        let mut res = Self::INVALID;
-        (|| res = get!().parse_keymap(keymap))();
-        res
-    }
+}
+
+pub fn parse_keymap(keymap: &str) -> Keymap {
+    get!(Keymap::INVALID).parse_keymap(keymap)
 }