config: add fullscreen window criteria

src/criteria/tlm/tlm_matchers/tlmm_fullscreen.rs

@@ -0,0 +1,11 @@
+use crate::{criteria::crit_graph::CritFixedRootCriterion, tree::ToplevelData};
+
+pub struct TlmMatchFullscreen(pub bool);
+
+fixed_root_criterion!(TlmMatchFullscreen, fullscreen);
+
+impl CritFixedRootCriterion<ToplevelData> for TlmMatchFullscreen {
+    fn matches(&self, data: &ToplevelData) -> bool {
+        data.is_fullscreen.get()
+    }
+}