README.md: add "commit message how-to" wiki link

Author: eriknyquist

README.md

@@ -21,6 +21,12 @@ Future upgrades may fail since the internal contents were modified by hand. In
 order to recover, shut down the IDE, delete the entire `Arduino15` directory,
 then restart the IDE.
 
+# Pull Requests
+
+Before submitting a pull request, please see our
+[guidelines](https://github.com/01org/corelibs-arduino101/wiki/Writing-a-commit-message)
+for writing a considerate commit message.
+
 # Support & Issues
 
 If you have found a bug, or you believe a new feature should be added, please
@@ -64,4 +70,4 @@ If you want to enable debug trace on Serail1 to debug corelib,  follow these ins
   * Find `compiler.cpp.flags` and add `-DCONFIGURE_DEBUG_CORELIB_ENABLED` at the end of this line
 4. Initial Serial1 in your sketch
   * Add `Serial1.begin(115200);` in your `setup()`
-5. Adjust the output level at log_init function in log.c
+5. Adjust the output level at log_init function in log.c