style(comments): set comment length to wrap at 100 chars

[joshka]

This is an opinionated default that helps avoid horizontal scrolling.
100 is the most common width on github rust projects and works well for
displaying code on a 16in macbook pro.

[codecov]

Codecov Report

Merging #218 (0cbc20b) into main (5243aa0) will increase coverage by 0.01%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main     #218      +/-   ##
==========================================
+ Coverage   81.66%   81.68%   +0.01%     
==========================================
  Files          34       34              
  Lines        6572     6579       +7     
==========================================
+ Hits         5367     5374       +7     
  Misses       1205     1205              

Impacted Files	Coverage Δ
src/lib.rs	100.00% <ø> (ø)
src/terminal.rs	55.64% <ø> (ø)
src/text.rs	69.74% <ø> (ø)
src/widgets/clear.rs	0.00% <ø> (ø)
src/widgets/mod.rs	66.66% <ø> (ø)
src/widgets/paragraph.rs	99.81% <ø> (ø)
src/buffer.rs	92.81% <100.00%> (ø)
src/widgets/chart.rs	95.94% <100.00%> (+<0.01%)	⬆️
src/widgets/reflow.rs	98.81% <100.00%> (+0.01%)	⬆️

[joshka]

This is related to a comment I made in #191 about the line length of a comment there.