Zufu Liu

Add issue #592 to track Export as HTML, RTF, PDF, LaTeX and XML.

Implemented by b718d0d48a60f69a2f23fe50b46b5ee1f15faa89 (however not works well for dark theme), feel free to test latest builds from main branch.

Support for default background color (e.g. dark theme) implemented by f60dd40b5b919797aeacd56d59c574f2a2f73c79.

I think this feature is completed, screenshot for "Copy as RTF" pasted into LibreOffice Writer and WordPad: https://github.com/zufuliu/notepad2/blob/8f6ad30c320795fcc80a9af769ddc43ec4e9afcb/locale/Locale.py#L26-L39 

`eolfilled` is implemented by 294b71bce761cb01dbf83b5648c1789f16c4b42d, only `overline` remains unimplemented (no RTF equivalent). 

Marked as fixed by e10af5ffcd7103c047f01ea155413cdf5f5ed37c, upstream Scintilla may have a different fix in the further we can switch to that at then.

This is now implemented (see https://sourceforge.net/p/scintilla/feature-requests/1310/), please test latest builds (e.g. from https://github.com/zufuliu/notepad2/actions/runs/4901319426).

This is due to the percent literal `%s.'".` is not recognized, filled https://github.com/ScintillaOrg/lexilla/issues/124.

Thanks, glade to see there is an ARM NEON version. Indeed the code is harder to read. about SSSE3, maybe following code is better (at least it's better for 32-bit...

Lexilla issue: https://github.com/ScintillaOrg/lexilla/issues/124