Store span of function argument colon tokens
diff --git a/syntax/tokens.rs b/syntax/tokens.rs
index c1a06a2..a668aa6 100644
--- a/syntax/tokens.rs
+++ b/syntax/tokens.rs
@@ -43,6 +43,7 @@
             attrs: _,
             visibility: _,
             name,
+            colon_token: _,
             ty,
         } = self;
         name.rust.to_tokens(tokens);