Remove yasnippet snipets submodule
Add upstream yasnippet-snippets repo as a submodule

In spacemacs/extensions/yasnippet-snippets
Update path to yasnippet-snippets submodule
Change binding to insert snippet from "hy" to "is"

"is" for Insert Snippet. Nice symmetry, much more quick
to type than "hy" which is convenient for a text insertion
command.
fixed C-j/C-k in auto-completion