Gather telemetry data for language-usage

[gracegoo-stripe]

We could do this on a per feature basis:
For hover-over reference, we log the method that matched but not the language the user was using. And, it looks like we are doing so in the vscode telemetry (vs. the google analytics):

vscode-stripe/src/stripeLanguageServer/server.ts

Line 92 in 18e2ce8

connection.telemetry.logEvent({name: 'ls.apihover', data: methodMatch});

.

Snippets are another language-specific feature. This is a built-in feature of VSCode so I don't know how we'd get data into GoogleAnalytics. There may be telemetry on this already -- if we could find where that is.