[Mousepad 0.5] Bump minimal required GtkSourceView to 3.24
Mousepad actually requires GtkSourceView
3.22 since d4e7368a, because of the use of gtk_source_search_context_*2()
functions, and I bump version to 3.24 in !46 (merged) (not included in Mousepad 0.5).
Although it is not absolutely needed in all these cases, I think it is not exaggerated to bump version to 3.24 and suppress the remaining GTK_SOURCE_CHECK_VERSION
, rather than adding new ones.