Ensure that the IME interface methods are all defined for both browser
and webview modes. Deprecate 'Element' methods and replace with
'TextStore' to clarify return type. Add deprecation flags where needed
and update documentation accordingly.
Fixes: #16144
Some pages were mentioning Keyman 17 although the content applies to
newer versions as well. This change therefore removes the version
number from those places.
Build-bot: skip
Test-bot: skip
Make the float UI KeymanWeb link point to the home for KeymanWeb, and
https rather than http, and update the helpURL documentation to match
the current endpoint.
Test-bot: skip
Build-bot: skip
Note: build.sh updated to make sure that test:help build action:target
doesn't also call test.sh by adding `:_all` meta-target.
Note: CI will need a new help-keyman-com.sh build step to deploy web
engine help.
Fixes: #12347