Update repo link to dotnet/runtime (dotnet#1781)

PATENTS.TXT

@@ -23,8 +23,7 @@ this promise.
 Definitions: 
 
 "Covered Code" means those Microsoft .NET libraries and runtime components as 
-made available by Microsoft at https://github.com/dotnet/coreclr, 
-https://github.com/dotnet/corefx and https://github.com/dotnet/corert.
+made available by Microsoft at https://github.com/dotnet/runtime.
 
 ".NET Patents" are those patent claims, both currently owned by Microsoft and 
 acquired in the future, that are necessarily infringed by Covered Code. .NET 
@@ -44,4 +43,4 @@ with (a) and (b).
 "Enabling Technology" means underlying or enabling technology that may be 
 used, combined, or distributed in connection with Microsoft's .NET Framework 
 or other .NET Runtimes, such as hardware, operating systems, and applications 
-that run on .NET Framework or other .NET Runtimes. 
+that run on .NET Framework or other .NET Runtimes.