all: remove unnecessary new line after return statements

[Tv0ridobro]

In some parts of the codebase, there are unnecessary newline characters following return statements. These newline characters create unnecessary separation in the code.

I searched for them with
rg -tgo -U 'return.*\n\n}'
and found 32 files and all new lines looks like a mistype.

I tried to think of a case where new line after return would be useful, but nothing came to mind. Maybe it would be better to remove them? Or even add new check to gofmt.

[gopherbot]

Change https://go.dev/cl/548316 mentions this issue: all: remove newline characters after return statements

[dmitshur]

Or even add new check to gofmt.

For reference, this is a part of functionality that gofumpt already implements.

[seankhliao]

i wish the go repos would use gofumpt