Update Documentation/building/windows/instructions.md

Co-authored-by: Jonathan Peppers <[email protected]>

Author: dellis1972

Documentation/building/windows/instructions.md

@@ -29,7 +29,7 @@ MSBuild version 15 or later is required.
 
  6. Build the project:
 
-        dotnet-local.cmd build Xamarin.Android.sln  -nr:false -m:1
+        dotnet-local.cmd build Xamarin.Android.sln -nr:false -m:1
 
  7. (For Microsoft team members only - Optional) In a [Developer Command
     Prompt][developer-prompt], build external proprietary git