fix trimming to inaccessible root path

[robjtede]

PR Type

Fix

PR Checklist

• Tests for the changes have been added / updated.
• Documentation comments have been added / updated.
• A changelog entry has been made for the appropriate packages.
• Format code with the latest stable rustfmt

Overview

When using TrailingSlash::Trim, the root path was getting trimmed to a blank string, making it inaccessible.

[codecov-commenter]

Codecov Report

Merging #1678 into master will increase coverage by 0.08%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #1678      +/-   ##
==========================================
+ Coverage   53.42%   53.51%   +0.08%     
==========================================
  Files         123      123              
  Lines       11855    11876      +21     
==========================================
+ Hits         6334     6355      +21     
  Misses       5521     5521              

Impacted Files	Coverage Δ
src/middleware/normalize.rs	98.33% <100.00%> (+0.35%)	⬆️

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[robjtede]

Anyone from @actix/contributors free to review this small fix? Could do with this getting released to make TrailingSlash::Trim usable.

[JohnTitor]

Looks good to me!