Different behaviour in regexp{..} for 'İ' and 'ß':
1.) lowercase routine for 'İ' gives 'İ', so that if we are searching
while ignoring case, the string '\dot{I}' is converted to '\dot{i}'.
In this case we have to change it to 'İ' (instead of 'i', as one would expect).
2.) If 'ß' is inserted via keybord on fresh created regexp box it appears as \lyxmathsym{ß},
if pasted from the lyx-screen it appears as \text{ß}
Fixes: #11508
Now there is the opposite case which needs to be addressed:
If no translation is available for a shortcut in a non-latin-scripted
document, we need to switch the language to English.
Xe/LuaTeX convert \AA to the deprecated character u212B (which is missing
in the default LatinModern font) instead of the recommended u00C5.
Also fix some of the "missing character" errors in Math.lyx if compiled with
Xe/LuaTeX which were caused by the replacement of \AA with literal u212B characters
in math-insets due to the old definitions in unicodesymbols.
Update the minimal example for failures of Math.lyx with system fonts.
From Günter:
> OK, so in TL18 the Ukrainean "auto-date" (7 березня 2019 р.) fails with
> PDF (XeTeX) and DVI (LuaTeX) but not PDF (LuaTeX).
> Strange. Feel free to invert.
Babel provides the \textlatin macro to ensure Latin letter ASCII characters are
output as Latin letters.
Instead of 8 different definitions for the several variants of the macro definition,
wrappers are individually added if required and available.
New bug in TeXLive 18.
Missing characters with XeTeX and wrong characters with LuaTeX.
Also:
* Remove spurious (Latin) characters from uk/Intro.lyx
* "wrong-output" tag for Cyrillic documents with XeTeX and TeX fonts.
1.) Added for 'breve' and 'grave' accents
2.) Corrected handling for 'i'-accents (allowed \hat{i} _and_ \hat{\imath})
because of problems with ignoring case
3.) Spaces: Changed some indents in source
The problem is the handling of regex as using math-mode. That is
any accented character is converted to a math macro.
For instance "ä" --> "\\ddot{a}".
Outside of math or regex it is not converted (if used xetex flavour),
but there are other chars which are converted in math and in text (but differently)
For instance "ů"
in math --> "\\mathring{u}"
in text --> "\\r{u}"
TODO: determine the still not handled conversions.
It would be nice, if we could persuade math factory to not convert
these characters, but I was unable to find the place where the
conversion actually takes place.
