feat(isRegExp): add `isRegExp` function

[hyesungoh]

close #299

Hi there, I appreciate your great works for environment!

I append isRegExp function.

[vercel[bot]]

The latest updates on your projects. Learn more about Vercel for Git ↗︎

Name	Status	Preview	Comments	Updated (UTC)
es-toolkit	✅ Ready (Inspect)	Visit Preview	💬 Add feedback	Aug 25, 2024 1:02pm

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 99.77%. Comparing base (d154184) to head (97840fa). Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #417   +/-   ##
=======================================
  Coverage   99.77%   99.77%           
=======================================
  Files         161      163    +2     
  Lines        1317     1321    +4     
  Branches      357      357           
=======================================
+ Hits         1314     1318    +4     
  Misses          2        2           
  Partials        1        1