Golang x/telemetry/config: add counters for refactoring operations

Summary

We have an ongoing project to improve refactoring tools in gopls (including rename, inline, change signature, and extract): https://github.com/orgs/golang/projects/39

Adding counters for these operations will help us understand whether the improvements we work on lead to any meaningful increase in the use of these tools.

Each of these counters measures how many times a user attempts to perform the operation, regardless of whether it succeeds: gopls/changesig - use of change signature gopls/rename - use of rename gopls/inline:{call,variable} - use of inline call or inline variable gopls/extract:{func,method,variable,variable-all} - use of extract function, method, variable, variable all

Gopls CL: https://go-review.git.corp.google.com/c/tools/+/680436

Proposed Config Change

https://go-review.git.corp.google.com/c/telemetry/+/680876

Comment From: findleyr

This makes sense to me. These would provide useful feedback as to whether our tools are being used, and potentially help us evaluate the effect of future improvements.