fix(scope-manager): support rest function type parameters

[bradzacher]

Fixes #2449

[typescript-eslint]

Thanks for the PR, @bradzacher!

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[codecov]

Codecov Report

Merging #2491 into master will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master    #2491   +/-   ##
=======================================
  Coverage   92.82%   92.82%           
=======================================
  Files         289      289           
  Lines        9294     9299    +5     
  Branches     2600     2602    +2     
=======================================
+ Hits         8627     8632    +5     
  Misses        321      321           
  Partials      346      346           

Flag	Coverage Δ
#unittest	92.82% <100.00%> (+<0.01%)	⬆️

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

Impacted Files	Coverage Δ
...ckages/scope-manager/src/referencer/TypeVisitor.ts	90.27% <100.00%> (+0.72%)	⬆️