fix(eslint-plugin): [explicit-member-accessibility] fix parameter properties bugs

[ankeetmaini]

Fixes #617
Fixes #857

[typescript-eslint]

Thanks for the PR, @ankeetmaini!

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[ankeetmaini]

This fixes most of the cases, there's just one gotcha, that parameter prop check will be skipped if constructors: off

[codecov]

Codecov Report

Merging #912 into master will increase coverage by <.01%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master     #912      +/-   ##
==========================================
+ Coverage   94.05%   94.06%   +<.01%     
==========================================
  Files         113      113              
  Lines        4931     4937       +6     
  Branches     1376     1378       +2     
==========================================
+ Hits         4638     4644       +6     
  Misses        166      166              
  Partials      127      127

Impacted Files	Coverage Δ
...-plugin/src/rules/explicit-member-accessibility.ts	90.74% <100%> (+1.15%)	⬆️

[ankeetmaini]

I am sorry, this is not a breaking change, as it doesn't change the existing config.

[bradzacher]

two comments, otherwise LGTM.
Thanks for taking the time to do this, and putting up with the churn!

[bradzacher]

I believe that this should also check for readonly.
public foo is valid (otherwise it's not a parameter property), but public readonly foo is not

Suggested change

	if (node.accessibility === 'public') {
	if (node.accessibility === 'public' && node.readonly) {

[ankeetmaini]

I checked public readonly foo in ASTExplorer using @typescript-eslint/parser, it showed that it is a valid AST.

https://astexplorer.net/#/gist/462492e71de4506a8ece6dbd055d2196/4273aa53fae3642835f358371cda2fe08e350bed

Also if I were to add that check, if parameterProperties='no-public', then public foo: string will pass as readonly is missing but still the access modifier is public.

[bradzacher]

For explicit:
public foo and public readonly foo are both considered valid (obviously!)

For no-public:
public foo is considered valid, because without public, it's not a parameter prop.

public readonly foo is considered invalid, because you can remove the accessibility modifier, and it's still a parameter property: readonly foo.

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We should probably document this in the readme so that it's a bit clearer, as I don't think that this is entirely intuitive.

[ankeetmaini]

I've incorporated these changes, thanks a lot for putting these down. HAve added in the readme too :)

[bradzacher]

LGTM! Thanks for doing this.