Add `gtk-doc-tools` as a dependency
Add gtk-doc-tools as a dependency since I received the following error before installing it:
subprojects/libinsane-gobject/doc/meson.build:4:10: ERROR: Program(s) ['gtkdoc-scan'] not found or not executable
Add gtk-doc-tools as a dependency since I received the following error before installing it:
subprojects/libinsane-gobject/doc/meson.build:4:10: ERROR: Program(s) ['gtkdoc-scan'] not found or not executable