melib/email/parser: ack \ as an atom

I think this is not spec compliant but the MIME spec (rfc6068 - The
'mailto' URI Scheme) uses it for "valid" addresses.

Signed-off-by: Manos Pitsidianakis <manos@pitsidianak.is>

melib/src/email/mailto.rs

@@ -368,16 +368,19 @@ mod tests {
         // Email address: "oh\\no"@example.org; corresponding 'mailto' URI:
 
         // <mailto:%22oh%5C%5Cno%22@example.org>.
+        assert_eq!(
+            mlt!("mailto:%22not%40me%22@example.org").address,
+            vec![addr!(r#""not@me"@example.org"#)]
+        );
 
         // Email address: "\\\"it's\ ugly\\\""@example.org; corresponding
         // 'mailto' URI:
 
         // <mailto:%22%5C%5C%5C%22it's%5C%20ugly%5C%5C%5C%22%22@example.org>.
-        // [ref:FIXME]
-        //assert_eq!(
-        //    mlt!("mailto:%22%5C%5C%5C%22it's%5C%20ugly%5C%5C%5C%22%22@example.org").
-        // address,    vec![addr!(r#"\"it's ugly\"@example.org"#)]
-        //);
+        assert_eq!(
+            mlt!("mailto:%22%5C%5C%5C%22it's%5C%20ugly%5C%5C%5C%22%22@example.org").address,
+            vec![addr!(r#""\\\"it's\ ugly\\\""@example.org"#)]
+        );
 
         // When an email address itself includes an "&" (ampersand) character, that
         // character has to be percent-encoded.  For example, the 'mailto' URI

melib/src/email/parser.rs

@@ -1413,7 +1413,7 @@ pub mod generic {
         if input[0].is_ascii_alphanumeric()
             || [
                 b'!', b'#', b'$', b'%', b'&', b'\'', b'*', b'+', b'-', b'/', b'=', b'?', b'^',
-                b'_', b'`', b'{', b'|', b'}', b'~',
+                b'_', b'`', b'{', b'|', b'}', b'~', b'\\',
             ]
             .contains(&input[0])
         {