PY-8427 Behave BDD support

PY-4186 Lettuce BDD tool support

 Step definition creation improved, inspection added

python/psi-api/src/com/jetbrains/python/psi/StructuredDocString.java

@@ -25,6 +25,15 @@ import java.util.List;
  * @author vlan
  */
 public interface StructuredDocString {
+  /**
+   * Creates parameter type documentation specific for certain doct type
+   * @param name param name
+   * @param type param type
+   * @return text to add to docsting
+   */
+  @NotNull
+  String createParameterType(@NotNull String name, @NotNull String type);
+
   String getDescription();
 
   String getSummary();