add support for comparing symbols

[mgred]

Purpose (TL;DR) - mandatory

Support comparing Symbol in samsam.

Discussion: #112

How to verify - mandatory

1. Check out this branch
2. npm install
3. npm test

Checklist for author

• npm run lint passes
• References to standard library functions are cached.

[codecov]

Codecov Report

Merging #127 into master will increase coverage by <.01%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master     #127      +/-   ##
==========================================
+ Coverage   99.79%   99.79%   +<.01%     
==========================================
  Files          25       25              
  Lines         491      493       +2     
==========================================
+ Hits          490      492       +2     
  Misses          1        1

Flag	Coverage Δ
#unit	99.79% <100%> (ø)	⬆️

Impacted Files	Coverage Δ
lib/match.js	100% <100%> (ø)	⬆️

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[mroderick]

I rebased the conflicts out of this PR and have merged it

[mroderick]

This has been published in @sinonjs/samsam@4.2.0