Add formatting codes to level 3 headings

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 dd94644..3911141 100644
--- a/docs/3.0-migration-guide.md
+++ b/docs/3.0-migration-guide.md
@@ -409,7 +409,7 @@
 instead, which also provides such upper bounds but takes more factors
 than just the MFL configuration into account.
 
-### Change MBEDTLS_ECP_FIXED_POINT_OPTIM behavior
+### Change `MBEDTLS_ECP_FIXED_POINT_OPTIM` behavior
 
 The option `MBEDTLS_ECP_FIXED_POINT_OPTIM` now increase code size and it does
 not increase peak RAM usage anymore.
@@ -419,7 +419,7 @@
 enabled curves. For example, for P-256 the difference is 1KB; see the documentation
 of this option for details.
 
-### Replaced MBEDTLS_SHA512_NO_SHA384 with MBEDTLS_SHA384_C
+### Replaced `MBEDTLS_SHA512_NO_SHA384` with `MBEDTLS_SHA384_C`
 
 This does not affect users who use the default `mbedtls_config.h`.
 MBEDTLS_SHA512_NO_SHA384 was disabled by default, now MBEDTLS_SHA384_C is
@@ -519,7 +519,7 @@
 was only needed when using a private key). This affects all applications using
 the RSA verify functions.
 
-### Remove the SSL API mbedtls_ssl_get_session_pointer()
+### Remove the SSL API `mbedtls_ssl_get_session_pointer()`
 
 This affects two classes of users:
 
@@ -585,7 +585,7 @@
 those reasons possible users should consider switching to modern and safe
 alternatives to be found in literature.
 
-### Remove MBEDTLS_SSL_DTLS_BADMAC_LIMIT option
+### Remove `MBEDTLS_SSL_DTLS_BADMAC_LIMIT` option
 
 This change does not affect users who used the default `mbedtls_config.h`, as the option
 MBEDTLS_SSL_DTLS_BADMAC_LIMIT was already on by default.
@@ -663,7 +663,7 @@
 The file `include/mbedtls/net.h` was removed because its only function was to
 include `mbedtls/net_sockets.h` which now should be included directly.
 
-### Remove MBEDTLS_CHECK_PARAMS option
+### Remove `MBEDTLS_CHECK_PARAMS` option
 
 This change does not affect users who use the default configuration; it only
 affects users who enabled that option.
@@ -696,7 +696,7 @@
 
 For more information see issue #4313.
 
-### Remove MBEDTLS_SSL_RECORD_CHECKING option and enable its action by default
+### Remove `MBEDTLS_SSL_RECORD_CHECKING` option and enable its action by default
 
 This change does not affect users who use the default mbedtls_config.h, as the
 option MBEDTLS_SSL_RECORD_CHECKING was already on by default.
@@ -815,7 +815,7 @@
     mbedtls_rsa_init(ctx);
 ```
 
-### Separated MBEDTLS_SHA224_C and MBEDTLS_SHA256_C
+### Separated `MBEDTLS_SHA224_C` and `MBEDTLS_SHA256_C`
 
 This does not affect users who use the default `mbedtls_config.h`. MBEDTLS_SHA256_C
 was enabled by default. Now both MBEDTLS_SHA256_C and MBEDTLS_SHA224_C are
@@ -893,7 +893,7 @@
 
 - all codes of the form `MBEDTLS_ERR_SSL_BAD_HS_XXX` have been replaced by various alternatives.
 
-### Modified semantics of mbedtls_ssl_{get,set}_session()
+### Modified semantics of `mbedtls_ssl_{get,set}_session()`
 
 This affects users who call `mbedtls_ssl_get_session()` or
 `mbedtls_ssl_set_session()` multiple times on the same SSL context
@@ -923,7 +923,7 @@
   calls. Applications achieve equivalent functional behavior by
   issuing only the very last call to `mbedtls_ssl_set_session()`.
 
-### Turn MBEDTLS_SSL_SRV_RESPECT_CLIENT_PREFERENCE configuration option into a runtime option
+### Turn `MBEDTLS_SSL_SRV_RESPECT_CLIENT_PREFERENCE` configuration option into a runtime option
 
 This change affects users who were enabling MBEDTLS_SSL_SRV_RESPECT_CLIENT_PREFERENCE
 option in the `mbedtls_config.h`