feat(eslint-plugin): [prom-func-async] report only function head

[phaux]

Depends on #2845.

Changes report location to be only the function head without the whole body, like in explicit-module-boundary-types.

[typescript-eslint]

Thanks for the PR, @phaux!

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The core maintainers work on this in their personal time, so please understand that it may not be possible for them to review your work immediately.

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[codecov]

Codecov Report

Merging #2872 (b14ae27) into master (5e2a993) will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master    #2872   +/-   ##
=======================================
  Coverage   92.87%   92.88%           
=======================================
  Files         314      315    +1     
  Lines       10670    10677    +7     
  Branches     3026     3028    +2     
=======================================
+ Hits         9910     9917    +7     
  Misses        344      344           
  Partials      416      416           

Flag	Coverage Δ
unittest	92.88% <100.00%> (+<0.01%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
.../eslint-plugin/src/rules/promise-function-async.ts	97.43% <100.00%> (+0.06%)	⬆️
.../eslint-plugin/src/util/explicitReturnTypeUtils.ts	100.00% <100.00%> (ø)
...kages/eslint-plugin/src/util/getFunctionHeadLoc.ts	100.00% <100.00%> (ø)

[bradzacher]

needs to be rebased on master.

changes itself LGTM!

[bradzacher]

while we're here - one case I believe this code doesn't correctly handle is decorators because decorators are included within the method's start.

Eg this code will highlight:

class Foo {
  @deco
  ^^^^^
  foo() {}
  ^^^^^
}

this has confused some people in the past (eg #751)

[phaux]

Sorry for not responding for so long. I had a break from open source. I will get to it on this weekend or maybe the next.

[bradzacher]

There's no rush! Whenever you're comfortable and ready.

[phaux]

Done!

[bradzacher]

thanks!