Fix typos prior to release

Signed-off-by: Tom Cosgrove <tom.cosgrove@arm.com>
diff --git a/include/mbedtls/config.h b/include/mbedtls/config.h
index 6912940..61db793 100644
--- a/include/mbedtls/config.h
+++ b/include/mbedtls/config.h
@@ -2427,7 +2427,7 @@
  *      MBEDTLS_TLS_PSK_WITH_RC4_128_SHA
  *
  * \warning   ARC4 is considered a weak cipher and its use constitutes a
- *            security risk. If possible, we recommend avoidng dependencies on
+ *            security risk. If possible, we recommend avoiding dependencies on
  *            it, and considering stronger ciphers instead.
  *
  */