Style: Spell out PMTU in ssl.h
@@ -1409,8 +1409,9 @@ void mbedtls_ssl_set_bio( mbedtls_ssl_context *ssl,
* encapsulation and encryption/authentication if any.
*
* \note This can be called at any point during the connection, for
- * example when a PMTU estimate becomes available from other
- * sources, such as lower (or higher) protocol layers.
+ * example when a Path Maximum Transfer Unit (PMTU)
+ * estimate becomes available from other sources,
+ * such as lower (or higher) protocol layers.
*
* \note This setting only controls the size of the packets we send,
* and does not restrict the size of the datagrams we're
