Fix typo in clear_caches docstring

jinja2/utils.py

@@ -109,7 +109,7 @@ def clear_caches():
     """Jinja2 keeps internal caches for environments and lexers.  These are
     used so that Jinja2 doesn't have to recreate environments and lexers all
     the time.  Normally you don't have to care about that but if you are
-    messuring memory consumption you may want to clean the caches.
+    measuring memory consumption you may want to clean the caches.
     """
     from jinja2.environment import _spontaneous_environments
     from jinja2.lexer import _lexer_cache