Snippets should not be returned unless client supports them

[puremourning]

According to LSP, snippet support is optional (a client capability).

If the client does not declare support for them, the server should not return them.

From the protocol:

			/**
			 * The client supports snippets as insert text.
			 *
			 * A snippet can define tab stops and placeholders with `$1`, `$2`
			 * and `${3:foo}`. `$0` defines the final tab stop, it defaults to
			 * the end of the snippet. Placeholders with equal identifiers are linked,
			 * that is typing in one will update others too.
			 */
			snippetSupport?: boolean;

[puremourning]

Thanks. Though I was sorta hoping to get plaintext completions rather than just suppressing them.