feat: add verb concept

wfassoc/tests/concept.rs

@@ -254,3 +254,25 @@ fn test_file_name() {
 }
 
 // endregion
+
+// region: Verb
+
+#[test]
+fn test_verb() {
+    fn ok_tester(s: &str) {
+        let rv = Verb::from_str(s);
+        assert!(rv.is_ok());
+        let rv = rv.unwrap();
+        assert_eq!(s, rv.inner());
+    }
+    fn err_tester(s: &str) {
+        let rv = Verb::from_str(s);
+        assert!(rv.is_err());
+    }
+
+    ok_tester("Open");
+    ok_tester("open");
+    err_tester("Space Name");
+}
+
+// endregion