Add type for implicit val

[travisbrown]

Meant to do this in #3188 but missed it.

[codecov-io]

Codecov Report

Merging #3191 into master will not change coverage.
The diff coverage is 100%.

@@           Coverage Diff           @@
##           master    #3191   +/-   ##
=======================================
  Coverage   92.99%   92.99%           
=======================================
  Files         376      376           
  Lines        7382     7382           
  Branches      195      195           
=======================================
  Hits         6865     6865           
  Misses        517      517

Flag	Coverage Δ
#scala_version_212	93.32% <100%> (+0.01%)	⬆️
#scala_version_213	90.56% <100%> (-0.02%)	⬇️

Impacted Files	Coverage Δ
...in/scala/cats/kernel/instances/CharInstances.scala	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 b3bc539...8ca7b08. Read the comment docs.