mailparsing: add Content-Disposition header

crates/mailparsing/src/header.rs

@@ -150,6 +150,10 @@ impl<'a> Header<'a> {
         Parser::parse_content_transfer_encoding_header(self.get_raw_value())
     }
 
+    pub fn as_content_disposition(&self) -> Result<MimeParameters> {
+        Parser::parse_content_transfer_encoding_header(self.get_raw_value())
+    }
+
     pub fn as_content_type(&self) -> Result<MimeParameters> {
         Parser::parse_content_type_header(self.get_raw_value())
     }

crates/mailparsing/src/headermap.rs

@@ -123,6 +123,12 @@ impl<'a> HeaderMap<'a> {
         as_content_transfer_encoding
     );
     accessor!(mime_version, "Mime-Version", String, as_unstructured);
+    accessor!(
+        content_disposition,
+        "Content-Disposition",
+        MimeParameters,
+        as_content_disposition
+    );
 
     accessor!(
         content_type,