Merge pull request dotnet#7126 from jbhensley/7119

Fix missing space

Author: eiriktsarpalis

xml/System.Linq/Enumerable.xml

@@ -11102,7 +11102,7 @@ If `count` is not a positive number, this method returns an identical copy of th
 ## Remarks  
  This method returns zero if `source` contains no elements.  
 
- The result doesnot include values that are `null`.  
+ The result does not include values that are `null`.  
 
  In Visual Basic query expression syntax, an `Aggregate Into Sum()` clause translates to an invocation of <xref:System.Linq.Enumerable.Sum%2A>.