Relax documentation of mbedtls_ssl_get_max_out_record_payload()

The previous documentation could be read as exhaustively listing
the factors that go into computing the maximum outgoing record
plaintext size -- we should give examples, but allow ourselves
to add more factors in the future.

Signed-off-by: Hanno Becker <hanno.becker@arm.com>
diff --git a/include/mbedtls/ssl.h b/include/mbedtls/ssl.h
index 905b567..9583dca 100644
--- a/include/mbedtls/ssl.h
+++ b/include/mbedtls/ssl.h
@@ -3647,10 +3647,10 @@
 
 /**
  * \brief          Return the current maximum outgoing record payload in bytes.
- *                 This takes into account the config.h setting \c
- *                 MBEDTLS_SSL_OUT_CONTENT_LEN, the configured and negotiated
- *                 max fragment length extension if used, and for DTLS the
- *                 path MTU as configured and current record expansion.
+ *                 This takes into account various factors, such as the config.h
+ *                 setting \c MBEDTLS_SSL_OUT_CONTENT_LEN, extensions such as the
+ *                 max fragment length or record size limit extension if used, and
+ *                 for DTLS the path MTU as configured and current record expansion.
  *
  * \note           With DTLS, \c mbedtls_ssl_write() will return an error if
  *                 called with a larger length value.