Move .nosearch to ./snippets subdirectory

Otherwise the command normal-top-level-add-subdirs-to-load-path
cannot be used to add yasnippet-snippets to the load-path.
This way, the package yasnippet-snippets is made available
but the actual snippets are not loaded as lisp code
(which would cause an error).

See also: 45a652e ("Create .nosearch", 2014-10-04)

Author: benzwick