Add link between sections

Signed-off-by: Dave Rodgman <dave.rodgman@arm.com>
diff --git a/docs/3.0-migration-guide.md b/docs/3.0-migration-guide.md
index 0ffd919..1546f4d 100644
--- a/docs/3.0-migration-guide.md
+++ b/docs/3.0-migration-guide.md
@@ -847,7 +847,7 @@
 1. Mbed TLS 3.0 does not offer a migration path for the use case 1: Like many
    other Mbed TLS structures, the structure of `mbedtls_ssl_session` is no
    longer part of the public API in Mbed TLS 3.0, and direct structure field
-   access is no longer supported. Please see the corresponding migration guide.
+   access is no longer supported. Please see the [section on private structure fields](#most-structure-fields-are-now-private) for more details.
 
 2. Users should replace calls to `mbedtls_ssl_get_session_pointer()` by
    calls to `mbedtls_ssl_get_session()` as demonstrated in the example