Minor fixes and improvements in TLS 1.3 key schedule documentation

Signed-off-by: Hanno Becker <hanno.becker@arm.com>
diff --git a/library/ssl_tls13_keys.h b/library/ssl_tls13_keys.h
index 7a9e5c9..73b8aaf 100644
--- a/library/ssl_tls13_keys.h
+++ b/library/ssl_tls13_keys.h
@@ -64,7 +64,7 @@
 #define MBEDTLS_SSL_TLS1_3_KEY_SCHEDULE_MAX_LABEL_LEN  \
     sizeof( union mbedtls_ssl_tls1_3_labels_union )
 
-/* The maximum length of HKDF contexts used in the TLS 1.3 standad.
+/* The maximum length of HKDF contexts used in the TLS 1.3 standard.
  * Since contexts are always hashes of message transcripts, this can
  * be approximated from above by the maximum hash size. */
 #define MBEDTLS_SSL_TLS1_3_KEY_SCHEDULE_MAX_CONTEXT_LEN  \
@@ -94,7 +94,7 @@
  *                  This must be a readable buffer of length \p clen Bytes.
  * \param clen      The length of \p context in Bytes.
  * \param buf       The destination buffer to hold the expanded secret.
- *                  This must be a writable buffe of length \p blen Bytes.
+ *                  This must be a writable buffer of length \p blen Bytes.
  * \param blen      The desired size of the expanded secret in Bytes.
  *
  * \returns         \c 0 on success.