Change only occurrence of -- to —

Author: MikeRalphson

versions/3.0.md

@@ -1466,7 +1466,7 @@ When passing complex objects in the `x-www-form-urlencoded` content type, the de
 
 It is common to use `multipart/form-data` as a `Content-Type` when transferring request bodies to operations.  In contrast to 2.0, a `schema` is required to define the input parameters to the operation when using `multipart` content.  This allows complex structures as well as supports mechanisms for multiple file uploads.
 
-When passing in `multipart` types, boundaries MAY be used to separate sections of the content being transferred--thus, the following default `Content-Type`s are defined for `multipart/*`:
+When passing in `multipart` types, boundaries MAY be used to separate sections of the content being transferred — thus, the following default `Content-Type`s are defined for `multipart/*`:
 
 * If the property is a primitive, or an array of primitive values, the default Content-Type is `text/plain`
 * If the property is complex, or an array of complex values, the default Content-Type is `application/json`