feat(eslint-plugin): add global modifier to naming-convention

[jharwig]

Fixes #2318

Added a new global modifier to the naming-convention rule. This is only valid for variable selectors with the const modifier. It allows for configuring top-level/global constants differently than constants defined inside nested function scopes.

Something to look at is the naming of global. The issue describes topLevel as another possible name. Another is whether this global modifier should be valid for function selectors (it is not in this PR.)

The implementation was based on the description of this comment in the issue

[typescript-eslint]

Thanks for the PR, @jharwig!

typescript-eslint is a 100% community driven project, and we are incredibly grateful that you are contributing to that community.

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.

Thanks again!

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[codecov]

Codecov Report

Merging #2691 into master will increase coverage by 0.02%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #2691      +/-   ##
==========================================
+ Coverage   92.79%   92.81%   +0.02%     
==========================================
  Files         294      294              
  Lines        9682     9686       +4     
  Branches     2717     2718       +1     
==========================================
+ Hits         8984     8990       +6     
+ Misses        330      329       -1     
+ Partials      368      367       -1     

Flag	Coverage Δ
#unittest	92.81% <100.00%> (+0.02%)	⬆️

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

Impacted Files	Coverage Δ
...kages/eslint-plugin/src/rules/naming-convention.ts	89.94% <100.00%> (+0.64%)	⬆️

[bradzacher]

code itself LGTM - just two comments on the tests - thanks for your work!

[bradzacher]

nit - you don't need to use the parserOptions here, and instead should do:

Suggested change

	parserOptions,
	parserOptions: {
	sourceType: 'script',
	},

[bradzacher]

Additionally, please duplicate this test case and additionally use sourceType: 'module' to ensure both scripts and modules work as expected.

[bradzacher]

Closing in favour of #2802