fix: better description for --no-watch-options-stdin

[snitin315]

What kind of change does this PR introduce?
fix

Did you add tests for your changes?
NA
If relevant, did you update the documentation?
NA
Summary
better description for --no-watch-options-stdin

Does this PR introduce a breaking change?
No

Other information
No

[codecov]

Codecov Report

Merging #2288 (673291d) into master (beea425) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #2288   +/-   ##
=======================================
  Coverage   67.78%   67.78%           
=======================================
  Files          63       63           
  Lines        2483     2483           
  Branches      570      570           
=======================================
  Hits         1683     1683           
  Misses        800      800           

Impacted Files	Coverage Δ
packages/webpack-cli/lib/utils/cli-flags.js	97.43% <ø> (ø)

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