Fix up the docs to mention the WKTs generated files also.

Fixes protocolbuffers#4277

objectivec/README.md

@@ -33,19 +33,21 @@ Building
 
 There are two ways to include the Runtime sources in your project:
 
-Add `objectivec/\*.h` & `objectivec/GPBProtocolBuffers.m` to your project.
+Add `objectivec/*.h`, `objectivec/google/protobuf/*.pbobjc.h`, and
+`objectivec/GPBProtocolBuffers.m` to your project.
 
 *or*
 
-Add `objectivec/\*.h` & `objectivec/\*.m` except for
+Add `objectivec/*.h`, `objectivec/google/protobuf/*.pbobjc.h`,
+`objectivec/google/protobuf/*.pbobjc.m`, and `objectivec/*.m` except for
 `objectivec/GPBProtocolBuffers.m` to your project.
 
 
 If the target is using ARC, remember to turn off ARC (`-fno-objc-arc`) for the
 `.m` files.
 
-The files generated by `protoc` for the `*.proto` files (`\*.pbobjc.h` and
-`\*.pbobjc.m`) are then also added to the target.
+The files generated by `protoc` for the `*.proto` files (`*.pbobjc.h` and
+`*.pbobjc.m`) are then also added to the target.
 
 Usage
 -----