Move Signature Help to features layer

[DustinCampbell]

This PR moves the internal Signature Help data API and provider model from the EditorFeatures layer to the Features layer. The code changes are pretty much exclusively mechanical.

cc @dotnet/roslyn-ide, @mattwar

[DustinCampbell]

test vsi please

[CyrusNajmabadi]

Looping in @vladima and @paulvanbrenk

Looks like this is a very minor change. But it may require some code updates in TS to point to new namespaces.

[CyrusNajmabadi]

👍

[mattwar]

👍

[DustinCampbell]

prtest/win/vsi/p2 -- CSharpInteractiveDirectives failed but passes for me locally. 😒

[DustinCampbell]

retest prtest/win/vsi/p2 please

[DustinCampbell]

prtest/win/vsi/p3 -- CSharpReplIntellisense failed but passes locally for me. 😒

[DustinCampbell]

retest prtest/win/vsi/p3 please

[DustinCampbell]

retest prtest/win/vsi/p0 please

[DustinCampbell]

retest prtest/win/vsi/p0 please

[DustinCampbell]

prtest/win/vsi/p0 -- BasicChangeSignatureDialog failed but passes locally for me. 😒

[DustinCampbell]

retest prtest/win/vsi/p0 please

[DustinCampbell]

retest prtest/win/vsi/p0 please

[DustinCampbell]

OK. Everything passed. @CyrusNajmabadi, should I wait for @vladima and @paulvanbrenk before merging?

[DustinCampbell]

OK, I heard back from @paulvanbrenk over email. The plan is to wait until after tonight's build and merge tomorrow.

[DustinCampbell]

Huh? All tests (including VSI) had passed on this PR and now there's suddenly new roslyn_prtest_win_vs* tests that got added with two failing? @jaredpar, do you know what this is? I hadn't seen anything in email about these.

[jaredpar]

@DustinCampbell I forwarded the email that discussed this change being made. Basically just moving the VSI tests over to generated jobs as we did for ETA. This PR hit the middle area where both the manual and generated jobs were in place. The switch is complete now.

I looked at the vsi0 failure and it appears tho job ran correctly here: used master on internal, sync'd to the PR commit and ran the correct BuildAndTest command.

[DustinCampbell]

retest roslyn_prtest_win_vsi0 please

[DustinCampbell]

OK, I can't figure out how to re-run these new jobs and get this PR to pick them up. Since all of the VSI tests had already passed with this change, I'm going to go ahead and merge optimistically.