fix typo in _issue_warning_captured doc

Author: blueyed

src/_pytest/warnings.py

@@ -138,7 +138,7 @@ def _issue_warning_captured(warning, hook, stacklevel):
     """
     This function should be used instead of calling ``warnings.warn`` directly when we are in the "configure" stage:
     at this point the actual options might not have been set, so we manually trigger the pytest_warning_captured
-    hook so we can display this warnings in the terminal. This is a hack until we can sort out #2891.
+    hook so we can display these warnings in the terminal. This is a hack until we can sort out #2891.
 
     :param warning: the warning instance.
     :param hook: the hook caller