Fixes 1398: deprecate Regiter_XXX_HandlerServer

[joesonw]

Gives deprecated notice when try to use Regiter_XXX_HandlerServer. Encourage using Register_XXX_FromEndpoint for full feature set and simplicity.

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[codecov-commenter]

Codecov Report

Merging #1399 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #1399   +/-   ##
=======================================
  Coverage   54.14%   54.14%           
=======================================
  Files          42       42           
  Lines        4375     4375           
=======================================
  Hits         2369     2369           
  Misses       1750     1750           
  Partials      256      256           

Impacted Files	Coverage Δ
...c-gen-grpc-gateway/internal/gengateway/template.go	80.58% <ø> (ø)

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[johanbrandhorst]

Thanks for opening the PR! Just a small note on the new additions.

[johanbrandhorst]

This is a little heavy handed, I don't think we need to use the word "deprecated", this feature was only added earlier this year, and it does serve some users needs.

Suggested change

	// Deprecated :consider using Register{{$svc.GetName}}{{$.RegisterFuncSuffix}}FromEndpoint instead. This will not provide grpc.ServerTransportStream https://github.com/grpc-ecosystem/grpc-gateway/issues/1398. This implementation will be missing certain features to behave like a standard stanalone grpc.Server.
	// Note that using this registration option will cause many gRPC library features (such as grpc.SendHeader, etc) to stop working . Consider using Register{{$svc.GetName}}{{$.RegisterFuncSuffix}}FromEndpoint instead.

[joesonw]

I wonder if there is a better way of warning people. In Goland, for example, It is really hard to notice the warnings, until you hover your cursor over the method for over a second or so and scroll all the way down to the note section.

[johanbrandhorst]

I don't think we need anything more than this. It's part of the documentation of the function, it should be one of the first places the user looks when using it.

[johanbrandhorst]

Thanks for your contribution! Could you cherry pick this against the v2 branch please?