Merge pull request #7678 from fr05t1k/master

Doc fix

examples/php/route_guide/README.md

 #gRPC Basics: PHP sample code
 
 The files in this folder are the samples used in [gRPC Basics: PHP][],
-a detailed tutorial for using gRPC in Ruby.
+a detailed tutorial for using gRPC in PHP.
 
 [gRPC Basics: PHP]:http://www.grpc.io/docs/tutorials/basic/php.html