minor doc patch for libtextstyle

[Simon Sobisch]

Adjusting outdated links and updates the status on hyperlinks in the 
terminal with OSR8 (operating system code 8).

Feel free to adjust as you see fit.

Simon



# libtextstyle/doc/libtextstyle.texi, 337-339
 You need a recent version of the respective terminal emulator program.
-See @url{https://gist.github.com/XVilka/8346728} for the most recent
+See @url{https://github.com/termstandard/colors} for the most recent
 developments in this area.


# libtextstyle/doc/libtextstyle.texi, 482-484
 (Cascading Style Sheet) syntax.  See
-@url{https://www.w3.org/TR/css2/cover.html} for a formal definition of
+@url{https://www.w3.org/TR/CSS22/} for a formal definition of
 CSS.  Many HTML authoring tutorials also contain explanations of CSS.

# libtextstyle/doc/libtextstyle.texi, 668-677
 Text output may contain hyperlinks.  These hyperlinks are encoded through
 an escape sequence, specified at
 @url{https://gist.github.com/egmontkob/eb114294efbcd5adb1944c9f3cb5feda,
-Hyperlinks in terminal emulators}.  Currently (as of 2019), they are
-displayed only in @code{gnome-terminal} version 3.26 or above.  More
+Hyperlinks in terminal emulators}.  Currently (as of 2024), they are
+displayed in many modern terminals, see
+@url{https://github.com/Alhadis/OSC8-Adoption, OSC8-Adoption}.  More
 terminal emulators will support hyperlinks in the future.  Terminal
 emulators which don't support hyperlinks ignore it, except for a few
 terminal emulators, for which users may need to disable the hyperlinks
 (see @ref{The NO_TERM_HYPERLINKS variable}) if the heuristic built into
 @code{libtextstyle} does not already disable them.