x/telemetry/config: add gopls/client:lsp-mode

[h9jiang]

Summary

Add gopls/client:lsp-mode enum value based on LSP clientInfo string provided by Emacs lsp-mode (introduced in https://go.dev/cl/825724).

Proposed Config Change

https://go.dev/cl/829245

[h9jiang]

cc @adonovan

(The name looks a little bit weird still, but name conflict should be rare.)

I will send email for review a week after.

[gopherbot]

Change https://go.dev/cl/829245 mentions this issue: internal/chartconfig: add lsp-mode to gopls/client

[gabyhelp]

Related Issues

• x/telemetry/config: add gopls/client:{helix,zed} #75332 (closed)
• x/telemetry/config: track additional client types in `gopls/client:*` #79916 (closed)
• x/telemetry/config: add collection for gopls/gotoolchain #68771 (closed)
• x/telemetry/config: collect gopls/telemetryprompt/accepted #68770 (closed)
• x/tools/gopls: collect editor kind information with telemetry #61038 (closed)
• x/telemetry/config: add counters for VulncheckMode options usage #75657 (closed)
• x/telemetry/config: add telemetry for package move refactoring #75612 (closed)
• x/telemetry/config: add counters for refactoring operations #74102 (closed)
• x/telemetry/config: add counters for MCP server usage #74341 (closed)
• x/tools/gopls: add windsurf and cursor bucket to the gopls/client counter #74874 (closed)

_{(Emoji vote if this was helpful or unhelpful; more detailed feedback welcome in this discussion.)}

[h9jiang]

Approved by @pjweinb @hyangah