Brief list of changes:
- names of some variables and constants were replaced for reading
convenience;
- URL-highlighting method moved to TextFormatter so URL's don't
conflict with italic text formatting;
- as I understand, in previous version 'file://' URL does not work
because of bad regex. I fix this with help of wiki page that
referenced in comment for old code. Important note: there are two
equal 'file://' URL syntax: 'file:///...' and 'file://localhost/...'
and the second one does NOT work in KDE but works in Gnome so that's
not a bug
Fix#4233
Added class provides text font formatting with HTML font tags
Supported stuff:
- nested formatting;
- several text pieces formatted with the same formatting style at the
one message;
- styling applies only if non-whitespace symbol follows opening
formatting symbol and also non-whitespace symbol preceds closing
symbol;
- only multiline code font formatting supports new line inside of
message text.
Also fix#3804
