Fix mistaken doc attribute in token module doc
diff --git a/src/token.rs b/src/token.rs
index b03d335..f1a2331 100644
--- a/src/token.rs
+++ b/src/token.rs
@@ -86,7 +86,7 @@
//! [Peeking]: ../parse/struct.ParseBuffer.html#method.peek
//! [Parsing]: ../parse/struct.ParseBuffer.html#method.parse
//! [Printing]: https://docs.rs/quote/0.6/quote/trait.ToTokens.html
-/// [`Span`]: https://docs.rs/proc-macro2/0.4/proc_macro2/struct.Span.html
+//! [`Span`]: https://docs.rs/proc-macro2/0.4/proc_macro2/struct.Span.html
use std;
#[cfg(feature = "extra-traits")]