curl.1: "a file", not an

docs/curl.1

@@ -526,8 +526,8 @@ or
 
 \fBcurl\fP -F "name=daniel;type=text/foo" url.com
 
-You can also explicitly change the name field of an file upload part by
-setting filename=, like this:
+You can also explicitly change the name field of a file upload part by setting
+filename=, like this:
 
 \fBcurl\fP -F "file=@localfile;filename=nameinpost" url.com