Loosen Fn trait bounds on fs::load_file

[sokorototo]

miniquad/src/fs.rs

Lines 31 to 44 in 8a15083

	/// Filesystem path on desktops or HTTP URL in WASM
	pub fn load_file<F: Fn(Response) + 'static>(path: &str, on_loaded: F) {
	#[cfg(target_arch = "wasm32")]
	wasm::load_file(path, on_loaded);
	#[cfg(target_os = "android")]
	load_file_android(path, on_loaded);
	#[cfg(target_os = "ios")]
	ios::load_file(path, on_loaded);
	#[cfg(not(any(target_arch = "wasm32", target_os = "android", target_os = "ios")))]
	load_file_desktop(path, on_loaded);
	}

fs::load_file is only expected to ever call its closure once, and thus only needs to implement FnOnce. Fn allows for the function to be called multiple times, and thus can't drop any wrapped values during its invocation. FnOnce is easier to implement and thus makes load_file easier to use.