Revert "UtBS::2: Reduced the effects of dehydration."

This reverts commit e81b89652ab651a7b975749295339d2a429d69a5.
It fixes part of bug #22790.
Remove fabi/fendrin from UtBS maintainers list

Done on his request.
Remove trailing whitespaces
Xcode project file update
Fixed bug #22800 and removed a redundant macro
A rough framework for an editor help section.

Still contains a lot non-sense and stubs.
Enable the early stage editor help section.
Jump right to the editor overview help topic in the editor.
add left click handler to labels
add to font::ttext an interface to pango fcn xy_to_index

This is used implicitly in the "get_column_line" function but
sometimes you just want the index, for instance, if you want to
resolve whether a link was clicked on.
get text index for a text label when it is clicked on
replace "get_string_index" with "get_token"

The get_token function, for a font::ttext, takes a coordinate
position and a list of delimiter characters, and returns the token
pointed to, if the position is in bounds, and the character being
pointed at is not itself a delimiter. Otherwise it returns the
empty string.

We also add some debugging output to the label click handler,
so that on log channel gui/event, we can see example tokens and
whether they look like URLs.
add support to open clicked links, after prompting user

If the user clicks on a token in a gui2 label that looks like a
link, prompt them if they want to open it.
add "link awareness" to font::ttext objects

If link awareness is enabled, then tokens that look like links
will be rendered thusly, and a "get_link" function is provided
to check if a layout location is pointing to a token which was
rendered as a link.
link-aware rendering of labels

This commit adds a new property of font::ttext, whether it is
"link aware". Link aware text has tokens that look like hyperlinks
formatted thusly, with coloration and an underline.

A `get_link` function, taking a layout location, returns a link
token if it is pointed to at that location, and link awareness
is enabled, and the empty string otherwise.

All gui2::tcontrols may now have their text labels set to be link
aware if desired. The gui2::tlabel constructor automatically sets
these to be link aware. The gui2::tlabel click handler is set to
use the `get_link` function instead of the `get_token` function.

Link awareness is also registered as a property of [text] fields in
gui widget definitions.