Depending on the device implementation, editor actions could be
received with different action ids or not at all for multi-line.
Added a parameter to virtual keyboards to properly handle single-line
and multi-line cases in all situations.
Single-line:
Input type set to text without multiline to make sure actions are sent.
IME options are set to DONE action to force action id consistency.
Multi-line:
Input type set to text and multiline to make sure enter triggers new lines.
Actions are disabled by the multiline flag, so '\n' characters are
handled in text changed callbacks.
Which means that reduz' beloved style which we all became used to
will now be changed automatically to remove the first empty line.
This makes us lean closer to 1TBS (the one true brace style) instead
of hybridating it with some Allman-inspired spacing.
There's still the case of braces around single-statement blocks that
needs to be addressed (but clang-format can't help with that, but
clang-tidy may if we agree about it).
Part of #33027.
