Remove deprecated snippets (#88)
Remove deprecated snippets (#88)

- PHP `<?php` snippet can't be used with supported hhvm versions.
 - fun is already a thing in the hack universe `fun('boolval')` creates a typed function reference. Needed to add a character to distinguish the two.
 - `include(_once)` and `require` is not recommended in hack anymore. I don't know how commonly they are used in the wild, but let's not encourage their use.

I was unsure about the array snippets, since they can be useful, but hack arrays should be the goto.
PranayAgarwal/vscode-hack