We can easily disable editing while the document is loading now that
GtkSourceBuffer has a loading property set via the GtkSourceFileLoader.

Fixes #645

There is no reason to keep them around if they're still loading beacuse
it's likely they're something we won't handle well.

We're specifically not supposed to do what we were doing, but it was at
the time the only way I found I could get things to break cycles. But with
how things are working now, we can switch this to forcing dispose on the
page and cleaning up template objects.

Fixes #651

Appstream decided to use reversed domains. Please merge before 46 if possible.

metainfo: Fix wrong developer id

See merge request GNOME/gnome-text-editor!145

Fixes #656

This makes things use what is upstream in GtkSourceView and Builder both.

We want this to render faster than it does currently which can be quite
slow on fractional scaling due to anti-aliasing with the border on
possibly merged pixels.

Remove this when GTK's NGL/Vulkan renderer does faster shadows and better
corner clipping w/ rounded borders (which will be needed even if the
shadow part is fixed).

This helps us avoid the overview map from damaging within the rounded
corners. Doing so can sigificantly speed up the renderer where we might
otherwise fail to hit our target framerate. This seems to affect us on
fractional scaling.

GTK 4.14.1 is going to have considerable performance improvements we've
been working through. This shouldn't warrant the same necessity that it
did previously.