If project uses C and does not include `stdbool.h`,
it will not have available lowercase booleans.
However, since this tool targets GLib programs,
we can rely on uppercase constants defined by GLib.

evolution-ews introduced a check for optional schemas, which would skip our hardcoded code paths.
https://gitlab.gnome.org/GNOME/evolution-ews/-/commit/a0c514bd345c67fe0fd2ed6ef48a25649b1f4d8e

Let’s update the semantic patch to also replace the invocations of specified `schemaExistsFunction` for known schemas with `true`.

This is useful for replacing code that cannot be easily handled by the generator,
such as the tentative settings constructor in e-d-s.

In addition to `g_settings_new`, there are three other GSettings constructors:
https://docs.gtk.org/gio/ctor.Settings.new.html