Add comment to quote_token about the tokens order

src/lib.rs

@@ -842,9 +842,9 @@ macro_rules! quote_token_with_context_spanned {
 }
 
 // These rules are ordered by approximate token frequency, at least for the
-// first 10 or so, to improve compile times. Having `ident` first is by far the
-// most important, because it's typically 2-3x more common than the next most
-// common token.
+// first 10 or so, to improve compile times. Similarly, having the `$tokens` at
+// the end allows for failing rules to fail as quickly as possible, and also helps
+// reduce compile times for crates that use `quote!` heavily.
 #[macro_export]
 #[doc(hidden)]
 macro_rules! quote_token {