lsp: remove notes .md file

This has moved to https://github.com/cue-lang/cue/wiki/cue-lsp for ease
of editing for now.

Signed-off-by: Paul Jolly <paul@myitcv.io>
Change-Id: Id21fab1e92319956feb2f8fb16b1fec7c81690d3
Dispatch-Trailer: {"type":"trybot","CL":1206612,"patchset":1,"ref":"refs/changes/12/1206612/1","targetBranch":"master"}