docs(eslint-plugin): [no-redeclare] clearly document type/variable redeclare case

[bradzacher]

Addresses #2477

[typescript-eslint]

Thanks for the PR, @bradzacher!

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 #2500 into master will decrease coverage by 0.01%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #2500      +/-   ##
==========================================
- Coverage   92.82%   92.80%   -0.02%     
==========================================
  Files         290      290              
  Lines        9393     9429      +36     
  Branches     2631     2638       +7     
==========================================
+ Hits         8719     8751      +32     
- Misses        322      323       +1     
- Partials      352      355       +3     

Flag	Coverage Δ
#unittest	92.80% <ø> (-0.02%)	⬇️

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

Impacted Files	Coverage Δ
packages/scope-manager/src/analyze.ts	72.41% <0.00%> (-4.51%)	⬇️
...ackages/scope-manager/src/referencer/Referencer.ts	93.93% <0.00%> (ø)