add caret as alternate keybinding for bol

[bjarthur]

for those who have ^ ingrained in their muscle memory.

see https://github.com/ronisbr/TerminalPager.jl/issues/27

[codecov-commenter]

Codecov Report

Merging #28 (94b3540) into main (4a2413d) will increase coverage by 0.10%. The diff coverage is n/a.

@@            Coverage Diff             @@
##             main      #28      +/-   ##
==========================================
+ Coverage   19.81%   19.91%   +0.10%     
==========================================
  Files          12       12              
  Lines         747      748       +1     
==========================================
+ Hits          148      149       +1     
  Misses        599      599              

Impacted Files	Coverage Δ
src/input/keybindings.jl	87.50% <ø> (ø)

... and 1 file with indirect coverage changes

[ronisbr]

Thanks!!