fix rst typos

Graph/graph/helpers.py

@@ -23,6 +23,11 @@ class AbstractQueue(metaclass=ABCMeta):
     def __contains__(self, item: Any) -> bool:
         return item in self._queue
 
+
+    def __str__(self):
+        return f"{self.__class__.__name__}({str(self._queue)[6:-1]})"
+
+
     @abstractmethod
     def add(self, item: Any) -> None:
         return None
@@ -36,7 +41,7 @@ class FIFO(AbstractQueue):
     """
     This structure allow to store any object,
     The First element add to the structure will be the First element removed from it.
-    *F*irst *I*n *F*irst *O*ut
+    **F**\ irst **I**\ n **F**\ irst **O**\ ut
     """
 
     def add(self, item: Any) -> Any:
@@ -65,7 +70,7 @@ class LIFO(AbstractQueue):
     """
     This structure allow to store any object,
     The Last element add to the structure will be the First element removed from it.
-    *L*ast *I*n *F*irst *O*ut
+    **L**\ ast **I**\ n **F**\ irst **O**\ ut
     """
 
     def add(self, item: Any) -> None: