iyi 0.16.2

About two hundred and sixty fixes, most of them found by comparing iyi
with Crystal, Python, libxml2, expat, PyYAML and the RFCs at scale -
random programs, documents, macro expressions, formatter mutants and
language-server sessions by the hundred thousand - each with a check
proven to fail without it. A when 1..5, a when of a tuple of types
and a when Int32 | String never matched and fell to else; a float
literal passed to a Float32 parameter rounded twice; fmt could change
a program's meaning (a heredoc's last blank line, - 1.abs, the end of a
line inside a string); a --release build wrote artifacts with no object
code; iterator adaptors copied their counts; std/json wrote bytes its
reader refused; std/xml took any byte past 0x7F for a name and wrote
whatever it was handed. Some answers change: Char#whitespace?
includes \v and \f, a negative shift count shifts the other way,
Int#chr takes all of Unicode, a flags enum with every member set prints
All, and std/yaml reads flow merges, tabs after indentation and -
continuations as the spec does.

Windows gains the windows-0.17.0-2 branch's fixes, and a program
there ends while another thread collects. The language server answers at
the cursor's line while a buffer does not compile, renames one method at
a time, and counts signature-help arguments correctly. .iyimod is
still v54, so 0.16.1's artifacts are rebuilt only because the compiler's
version is in their identity.