internal/lsp/source: filter out comparable from completion results
internal/lsp/source: filter out comparable from completion results

The comparable interface is introduced on the dev.typeparams branch.
Filter it out from gopls completion results so that it doesn't break
tests on the dev.typeparams branch.

Change-Id: Iba22c0980c09e99b454ce9e22813cc3a1f94a90c
Reviewed-on: https://go-review.googlesource.com/c/tools/+/293931
Trust: Robert Findley <9179eee875d1ee628c37fb47d7e749e855ffd21f@google.com>
Run-TryBot: Robert Findley <9179eee875d1ee628c37fb47d7e749e855ffd21f@google.com>
Reviewed-by: Rebecca Stambler <d7cf11e5f299d88ea8348366a9fc4f7c335c3afa@golang.org>
gopls-CI: kokoro <2ac7b1f3fa578934c95181d4272be0d3bca00121@google.com>
TryBot-Result: Go Bot <66cb808b70d30c07676d5e946fee83fd561249e5@golang.org>

golang/tools,golang/tools,golang/tools,golang/tools,golang/tools