Add missing "is" in OT shim docs
@@ -496,7 +496,7 @@ class ScopeManagerShim(ScopeManager):
span.
Warning:
- This property is *not* a part of the OpenTracing API. It used
+ This property is *not* a part of the OpenTracing API. It is used
internally by the current implementation of the OpenTracing shim
and will likely be removed in future versions.
"""
