vkeyMaps table compiler, unit test, and fixes to json schema. Adds a
vkeyMaps entry to the basic e2e test.

us-virtual-keys.ts has a new mapping for CLDR VKey Enums, but I will
tweak this in an upcoming commit to use constants instead of hard-coded
values.

Just wanted to rename this to make it clearer. Also added a prefix to
each message generator to indicate the type of message, as otherwise it
is not obvious within the compiler which messages are going to cause the
compiler to fail.

Note that the message generator function prefixes are Title Cased
whereas the message identifier constant prefixes are CAPS. I guess this
could be confusing but I think it works okay in practice.

If a loca entry is either formatted wrongly (e.g. wrong case), or is
not minimal, then the compiler will now report a hint.

Just reorders all work around the various sections to match the binary
format order -- that is, 'sect' first, then all other sections
alphabetically.

This also means the compiler now emits the sections in the expected
order.

No other changes to functionality.

Updates compiler, headers and documentation for the 'name' section,
which will always be present as the LDML keyboard spec requires at least
one name in the `<names>` element.

Also uses `index()` to get count of strings automatically.

Reformat basic.txt to make it more readable as it will get less
'basic' over time!

Adds an `index` command as suggested by #7186.

> Future enhancement suggestion: include ... index() for block indices
> within these repeated blocks. Would be very useful for string tables
> in the example ref.

Also adds semver package for validating the version field.

This makes it easier to write a binary file which contains offsets and
size values. Using this for unit tests for the LDML keyboard compiler.

Example kmldmlc basic.txt is updated and included.

Future enhancement suggestion: include count() for repeated blocks and
index() for block indices within these repeated blocks. Would be very
useful for string tables in the example ref.

This is reasonably random, but wanted to add another test for content
rather than structure, just to verify that the DTD-XSD-jsonschema
translation is doing the right thing according to what we expect.

Looking good.

As we do not appear to have access to a good DTD validation library in
Node.js, we will instead convert the DTD to a JSON schema file and use
that for validation.

I have not verified every aspect of the JSON schema at this point, but
will incrementally do so as I implement further aspects of the compiler.

This updates all the testing to use the schema. As the schema validation
is slow, I have increased the 'normal' time for tests.

Also removes `-test` from normal `make build` for kmlmc, moving that
responsibility to `make test` (but uses `-tdd` to avoid rebuild).

feat(developer): loca minimization + cleanup kmldmlc error list 🙀

feat(developer): add loca tests 🙀

chore(core): split out validators 🙀

feat(developer): add unit tests for meta compiler 🙀

- copy over asserts from 'old' code

#7136

yes, a kmxplus file does not start with a 'sect' !

#7136

#7136

chore: merge master into feature-ldml 🙀

Yeah two for the price of one:

- minimize locales at compile time
- cleans up the list of errors to make it easier to maintain and use

Note: bumps target to es2020 for better Intl.* support. Verified as
supported by Node 16+ and modern browsers.

Adds support for multiple locales and basic canonicalization. Does not
support normalization of locales.

chore(developer): Merge branch 'chore/merge-master-into-feature-ldml' into feat/developer/kmldmlc-meta-tests-and-cleanup

Merge pull request #7153 from keymanapp/refactor/developer/kmldmlc-pure-functional-section-compilers

refactor(developer): each section compiler is a pure function 🙀

feat(core): set -DDEBUG for debug 🙀

auto: increment master version to 16.0.55

- set -DDEBUG for 'debug' meson builds
- default KXPLUS_DEBUG  to 1 for -DDEBUG

#7136

First, a little bit of refactoring to make it cleaner to do unit test
for each section.

Then add some global error values.

Throw in a helper function or two.

Dust off the edges of the CompilerCallbacks object.

Duct tape together validation of the normalization attribute.

And ... eventually we get a nice clean-like unit test for the meta
compiler, with three pretty little fixtures and as-neat-as-you-like-it
assertions.