don't add backslashes to tag on transform format

adding backslashes breaks the `[+1-1]` or `[+1]` tag upon the first save. e.g. `[+1]` is transformed to

    \[+1:f87d7cdfc2b7463415e72106d80c4899\]

but should really be transformed to

    [+1:f87d7cdfc2b7463415e72106d80c4899]