Fix links in NDEF.md

Add missing links.

Author: Amanda Butler

docs/reference/api/connectivity/nfc/NDEF.md

@@ -77,7 +77,9 @@ void parse_ndef_message(const Span<const uint8_t> &buffer) {
 
 An application can extend capabilities of `SimpleMessageParser` by adding new record parsers (`mbed::nfc::ndef::RecordParser`) at runtime.
 
-[![View code](https://www.mbed.com/embed/?type=library)](http://os-doc-builder.test.mbed.com/docs/development/mbed-os-api-doxy/FIXME)
+[![View code](https://www.mbed.com/embed/?type=library)](http://os-doc-builder.test.mbed.com/docs/development/mbed-os-api-doxy/classmbed_1_1nfc_1_1ndef_1_1_message_parser.html)
+
+[![View code](https://www.mbed.com/embed/?type=library)](http://os-doc-builder.test.mbed.com/docs/development/mbed-os-api-doxy/classmbed_1_1nfc_1_1ndef_1_1common_1_1_simple_message_parser.html)
 
 #### Construction
 
@@ -103,4 +105,4 @@ size_t build_ndef_message(const Span<uint8_t> &buffer) {
 }
 ```
 
-[![View code](https://www.mbed.com/embed/?type=library)](http://os-doc-builder.test.mbed.com/docs/development/mbed-os-api-doxy/FIXME)
+[![View code](https://www.mbed.com/embed/?type=library)](http://os-doc-builder.test.mbed.com/docs/development/mbed-os-api-doxy/classmbed_1_1nfc_1_1ndef_1_1_message_builder.html)