macos: Escape filename properly

shellescape() is not quite correct, as it also adds single quotes around
otherwise proper filenames, e.g. it turns test into 'test', which
jobstart() will complain about in neovim.

The regression was introduced in
145a2fd to fix the problem with spaces
in the filename in #13.
Because vim's job_start() implementation is a little more robust than
the neovim counterpart and can handle the single quotes, noone noticed
the problem back then.

To fix this we switch to fnameescape(), which doesn't enclose everything
in quotes but rather escapes every problematic character individually,
e.g. test turns into test, and test asdf turns into test\ asdf.

Fixes #14

Author: vimpostor

autoload/lumen/platforms/macos.vim

@@ -1,4 +1,4 @@
-let s:exe = shellescape(resolve(expand('<sfile>:p:h')) . '/macos/watcher')
+let s:exe = fnameescape(resolve(expand('<sfile>:p:h')) . '/macos/watcher')
 
 func lumen#platforms#macos#watch_cmd()
 	return [s:exe]