Rename flex-no-wrap to flex-nowrap

[adamwathan]

This PR is basically the opposite of #2675, and renames flex-no-wrap to flex-nowrap to be consistent with whitespace-nowrap if we choose to keep that change. Going to just leave both open until I decide what to do 🤔

[codecov-io]

Codecov Report

Merging #2676 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #2676   +/-   ##
=======================================
  Coverage   92.99%   92.99%           
=======================================
  Files         172      172           
  Lines        1727     1727           
  Branches      304      304           
=======================================
  Hits         1606     1606           
  Misses        104      104           
  Partials       17       17           

Impacted Files	Coverage Δ
src/plugins/flexWrap.js	100.00% <ø> (ø)

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