clean up 'recursive' parser description

[colin-m-davis]

The comment for the recursive parser has a spelling error and its grammar could be improved. This is a very simple pull request that addresses these things!

Thank you for contributing to cats-parse!

This is a kind reminder to run sbt prePR and commit the changed files, if any, before submitting.

[codecov-commenter]

Codecov Report

Merging #523 (2eb95eb) into main (5c7296b) will increase coverage by 0.13%.
Report is 1 commits behind head on main.
The diff coverage is n/a.

❗ Current head 2eb95eb differs from pull request most recent head 3cfe080. Consider uploading reports for the commit 3cfe080 to get more accurate results

@@            Coverage Diff             @@
##             main     #523      +/-   ##
==========================================
+ Coverage   95.06%   95.20%   +0.13%     
==========================================
  Files          10       10              
  Lines        1480     1480              
  Branches      359      359              
==========================================
+ Hits         1407     1409       +2     
+ Misses         73       71       -2     

Files Changed	Coverage Δ
core/shared/src/main/scala/cats/parse/Parser.scala	94.59% <ø> (+0.08%)	⬆️

... and 1 file with indirect coverage changes