Adds Into<Value>, Into<Element> impl for all ints

[zslayton]

Adds a blanket implementation of Into<Value> for all integer types, which allows them to transitively benefit from the Into<Element> implementation that exists for T: Into<Element>.

Fixes #573.

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[codecov]

Codecov Report

Patch coverage: 100.00% and project coverage change: +0.02 🎉

Comparison is base (66a3194) 83.32% compared to head (79ea837) 83.35%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #574      +/-   ##
==========================================
+ Coverage   83.32%   83.35%   +0.02%     
==========================================
  Files         104      104              
  Lines       19675    19671       -4     
  Branches    19675    19671       -4     
==========================================
+ Hits        16395    16397       +2     
+ Misses       1742     1736       -6     
  Partials     1538     1538              

Impacted Files	Coverage Δ
src/types/integer.rs	80.65% <ø> (+2.18%)	⬆️
src/element/mod.rs	89.37% <100.00%> (-0.06%)	⬇️

☔ View full report in Codecov by Sentry.
📢 Do you have feedback about the report comment? Let us know in this issue.