feat(multiselect): option to change checkmarks

[KarolosLykos]

Description

Added the option to define the checkmarks in the interactive multiselect printer.
Also added some basic test cases.

Scope

What is affected by this pull request?

• Bug Fix
• New Feature
• Documentation
• Other

Related Issue

Fixes #418

To-Do Checklist

• I tested my changes
• I have commented every method that I created/changed
• I updated the examples to fit with my changes
• I have added tests for my newly created methods

[codecov]

Codecov Report

Merging #429 (2806031) into master (c1e924e) will increase coverage by 4.57%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master     #429      +/-   ##
==========================================
+ Coverage   81.52%   86.10%   +4.57%     
==========================================
  Files          29       29              
  Lines        2106     2108       +2     
==========================================
+ Hits         1717     1815      +98     
+ Misses        372      263     -109     
- Partials       17       30      +13     

Impacted Files	Coverage Δ
atoms.go	100.00% <ø> (ø)
interactive_multiselect_printer.go	54.44% <100.00%> (+54.44%)	⬆️

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[MarvinJWendt]

Thanks for the PR, really appreciate it. Just some nitpicking stuff, otherwise it looks good 👍

[MarvinJWendt]

LGTM! Thanks for contributing 🎉 🚀

[MarvinJWendt]

I have made some additional changes to enable changing the checkmarks via a custom theme. Should be pushed soon.

[KarolosLykos]

I have made some additional changes to enable changing the checkmarks via a custom theme. Should be pushed soon.

Yes, I was thinking adding that myself. That's great!!!