We fairly consistently had multiple monitors with the whole
vendor,product,serial tuple identical. If we start relying on making
monitors a bit more unique, e.g. for colord integration, we need to make
two monitors connected distinguishable in order for tests to properly
reflect reality and excercise the correct colord integration paths.
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2141>
Makes sure that monitor specs which may be read from EDID data do not
contain characters that are invalid in XML. Makes it possible to restore
monitor configs of monitor models with characters such as '&' in them.
To make this change not break any tests, the sample monitor configs need
to be adjusted as well. Apostrophes don't strictly have to be escaped in
XML text elements. However, we now do escape the elements in
`<monitorspec>` specifically.
Closes: <https://gitlab.gnome.org/GNOME/mutter/-/issues/1011>
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1685>
