[ANN] sexp_processor 4.16.0 Released

sexp_processor version 4.16.0 has been released!

* home: <GitHub - seattlerb/sexp_processor>
* rdoc: <sexp_processor-4.15.3 Documentation>

sexp_processor branches from ParseTree bringing all the generic sexp
processing tools with it. Sexp, SexpProcessor, Environment, etc... all
for your language processing pleasure.

Changes:

### 4.16.0 / 2021-10-27

* 4 minor enhancements:

  * Added Sexp#value (pushed up from ruby_parser).
  * Aliased Sexp#concat to #_concat and use that so it can be overridden.
  * Cache the #hash result.
  * StrictSexp mode (4) now covers concat.

* 3 bug fixes:

  * Fix some doco on each_sexp to clarify that it is not recursive.
  * Fixed a bug calling enum_for when using each_of_type w/ no block.
  * Minor fixes to pt_testcase.rb for custom timeouts and better error handling.