x/telemetry/config: add gopls/client:{helix,zed}

[adonovan]

Summary

Add gopls/client:{helix,zed} enum values based on LSP clientInfo string provided by popular text editors.

Proposed Config Change

https://go.devl/cl/702118

[findleyr]

SGTM. These are popular editors, and might help explain our increasingly large "Other" bucket.

This seems entirely uncontroversial, but lets leave it open for a week for comments.

[gopherbot]

Change https://go.dev/cl/702118 mentions this issue: internal/chartconfig: add counter: gopls/client:{helix,zed}