(doc) fix 0.14 migration guide broken links (#5278)

site/src/main/paradox/releases/migrations/v0.14.0-Migration-Guide.md

@@ -14,7 +14,7 @@ If the type is or contains an Avro class (either `GenericRecord` or a `SpecificR
 you can import the `com.spotify.scio.avro._` package to get the implicit avro coders back in scope. This is likely to happen
 if you are using any `readAsAvro..` API or `AvroSortedBucketIO` from `scio-smb`. See [avro removed from core](#avro-removed-from-core) for more details.
 
-If the type relied on a fallback coder, we advise you to create a custom coder. See [coders](../../internals/Coders.md/#how-to-build-a-custom-coder) for more details.
+If the type relied on a fallback coder, we advise you to create a custom coder. See @ref:[coders](../../internals/Coders.md#how-to-build-a-custom-coder) for more details.
 If you want to use kryo implicit fallback coders as before, this requires now to import `com.spotify.scio.coders.kryo._` explicitly.
 
 ## Avro removed from core
@@ -69,4 +69,4 @@ to the official [metadata](https://github.com/tensorflow/metadata) API.
 ## scio-smb provided implementations
 
 When using `scio-smb`, you also need to depend on the scio module that provides the file format implementation you want to use.
-See [Sort-Merge-Bucket](../../extras/Sort-Merge-Bucket.md/#what-kind-of-data-can-i-write-using-smb-) for more details.
+See @ref:[Sort-Merge-Bucket](../../extras/Sort-Merge-Bucket.md#what-kind-of-data-can-i-write-using-smb-) for more details.