Consider Adding a `ExtensionVersion` to `ClientInfo`

[davidbarsky]

Hello! I was wondering if y'all would accept a PR to add an ExtensionVersion to ClientInfo?

vscode-languageserver-node/protocol/src/common/protocol.ts

Lines 1389 to 1399 in 0280642

	export interface ClientInfo {
	/**
	* The name of the client as defined by the client.
	*/
	name: string;
	/**
	* The client's version as defined by the client.
	*/
	version?: string;
	}

(I'd also be okay with a grab-bag object of object!)

[dbaeumer]

I am not against this. But it would need to go into the specification as well (https://microsoft.github.io/language-server-protocol/)