x/tools/gopls: SignatureHelp activeParameter always 0 after v0.18.1

[skewb1k]

After commit 2880aae, SignatureInformation.activeParameter does not have omitempty tag and always marshal. The problem is that its never assigned to anything and always 0, which overrides actual value in SignatureHelp.activeParameter, as stated in spec.

Solution is have same value as in SignatureHelp.activeParameter in SignatureInformation.activeParameter. The fix is minimal—just a one-line change —and I've submitted a PR.

[gopherbot]

Change https://go.dev/cl/683135 mentions this issue: gopls: fix SignatureHelp activeParameter not being passed