Add link to crc.md

Add link to Doxygen.

Author: Amanda Butler

docs/reference/contributing/target/crc.md

@@ -29,9 +29,7 @@ The hardware CRC module in the MCU that supports at least one of the following d
 
 You can find the API and specification for the hardware CRC API in the following header file:
 
-```
-Fix link after code is merged.
-```
+[![View code](https://www.mbed.com/embed/?type=library)](http://os-doc-builder.test.mbed.com/docs/development/mbed-os-api-doxy/group__hal__crc.html)
 
 To enable hardware CRC support in Mbed OS, add the `CRC` label in the `device_has` option of the target's section in the `targets.json` file.