Add metasearch2 to projects using fend in readme

[mat-1]

I've been using fend to power the calculator in my personal metasearch engine and I've been very happy with it. Here's the part of my code that calls fend: https://github.com/mat-1/metasearch2/blob/master/src/engines/answer/calc.rs

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (bb43194) 83.27% compared to head (8e9a7fc) 83.27%.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #263   +/-   ##
=======================================
  Coverage   83.27%   83.27%           
=======================================
  Files          52       52           
  Lines       14518    14518           
=======================================
  Hits        12090    12090           
  Misses       2428     2428           

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[printfn]

Awesome, it’s great that you’re finding fend useful!