fix several format and comment issues

Signed-off-by: Jerry Yu <jerry.h.yu@arm.com>
diff --git a/include/mbedtls/ssl.h b/include/mbedtls/ssl.h
index 70dc501..d328d23 100644
--- a/include/mbedtls/ssl.h
+++ b/include/mbedtls/ssl.h
@@ -2582,7 +2582,7 @@
  *                      the server supports.
  *
  * \warning             The ciphersuites array \p ciphersuites is not copied.
- *                      It must remain valid for the lifetime the SSL
+ *                      It must remain valid for the lifetime of the SSL
  *                      configuration \p conf.
  *
  * \param conf          The SSL configuration to modify.