fix typo

Author: valerii15298

src/oas.md

@@ -1849,7 +1849,7 @@ However, this is not guaranteed, so it may be more interoperable to keep the pad
 
 See [Encoding Usage and Restrictions](#encoding-usage-and-restrictions) for guidance on correlating schema properties with parts.
 
-Note that there are significant restrictions on what headers can be used with `multipart` media types in general ([RFC2046](https://www.rfc-editor.org/rfc/rfc2046.html#section-5.1)) and `multi-part/form-data` in particular ([RFC7578](https://www.rfc-editor.org/rfc/rfc7578.html#section-4.8)).
+Note that there are significant restrictions on what headers can be used with `multipart` media types in general ([RFC2046](https://www.rfc-editor.org/rfc/rfc2046.html#section-5.1)) and `multipart/form-data` in particular ([RFC7578](https://www.rfc-editor.org/rfc/rfc7578.html#section-4.8)).
 
 ##### Handling Multiple `contentType` Values