chore(developer,core): change sample and test files to use \u{…} 🙀

feat(core): unescape u 🙀

fix(ios): banner image management

Merge branch 'feat/core/10319-escaping-you-epic-ldml' into feat/developer/10319-remove-old-escape-epic-ldml

For: #10319

- don't try to remove irregular sentinel sequences
- update test

For: #10319

- remove stray change to kmx_processevent.cpp
- fix escaping of syntax chars
- fix comment per review

For: #10319

auto: increment master version to 17.0.247

fix(web): right-flick gesture-preview positioning

docs(linux): Add documentation for Core API verification

Co-authored-by: Marc Durdin <marc@durdin.net>

docs(common): Update website README.md

chore(common): Update crowdin strings for Khmer

fix(web): Add null check for changing the keyboard during typing

Closes #10405.

auto: increment master version to 17.0.246

* update configure step about downloading _common/ files
* Add info about website-local-proxy

feat(developer): add `-m` parameter to kmc to control message severity

fix(android): Fix OSK rotation issues

- #10389 will require this, but at least change the test files

#10319

- \u{0300} needs to turn back into an actual char, so normalization gets an opportunity to run.

#10319

chore(core): Ignore C++ symbols

- improved test code and marker parsing

#10319

- basic.txt fixup

#10319

auto: increment master version to 17.0.245

We have a C API, but (internal) C++ template instantiations are visible
and so get flagged by `dpkg-gensymbols`. This change ignores the one
use of C++ by marking it optional. This is listed as a usage scenario
in the dpkg-gensymbols man page.

Note this requires a change how we call dpkg-gensymbols: if the `-O`
parameter is specified, the file is not treated as being a template file
(see man deb-src-symbols) and so the tags are not interpreted.
Additionally the file gets overwritten with the non-tag version. So this
change removes the `-O` parameter, and changes the archiving of the
generated file.

docs(linux): Update sample settings

fix(web): use KMW OSK font for "**" special-text in key hints

Co-authored-by: Eberhard Beilharz <ermshiperete@users.noreply.github.com>

feat(developer): warn on gesture support for downlevel

refactor(core): Move `km_core_state_context_*` tests to separate file

- escaping working, matching not yet

#10319

- match sentinels as \\u…
- support \Uxxxxxxxx for >0xffff
- more escaping stuff

#10319