Allow to set a footer in the description

[lambdafu]

Let's see what you think :) Setting a footer for a bug report address or other notes is common enough that I think it should be supported without subclassing. If you agree, here is a simple implementation that does the trick for me.

[codecov]

Codecov Report

Merging #42 into master will not change coverage.
The diff coverage is 100%.

@@          Coverage Diff          @@
##           master    #42   +/-   ##
=====================================
  Coverage     100%   100%           
=====================================
  Files           9      9           
  Lines        1168   1173    +5     
  Branches      239    240    +1     
=====================================
+ Hits         1168   1173    +5

Impacted Files	Coverage Δ
include/CLI/App.hpp	100% <100%> (ø)	⬆️

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[codecov]

Codecov Report

Merging #42 into master will not change coverage.
The diff coverage is 100%.

@@          Coverage Diff          @@
##           master    #42   +/-   ##
=====================================
  Coverage     100%   100%           
=====================================
  Files           9      9           
  Lines        1168   1171    +3     
  Branches      239    240    +1     
=====================================
+ Hits         1168   1171    +3

Impacted Files	Coverage Δ
include/CLI/App.hpp	100% <100%> (ø)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 1b02682...c9a3ee5. Read the comment docs.

[henryiii]

I think these both look good. Will check and merge tomorrow. Don't worry about the formatting check, I can run clang-format.

[henryiii]

Thanks! I already have a use case, I believe, in a program I'm working on! 👍