reference: add link to the symbols

Author: tshepang

src/doc/reference.md

@@ -419,10 +419,13 @@ The two values of the boolean type are written `true` and `false`.
 ### Symbols
 
 Symbols are a general class of printable [tokens](#tokens) that play structural
-roles in a variety of grammar productions. They are cataloged here for
-completeness as the set of remaining miscellaneous printable tokens that do not
+roles in a variety of grammar productions. They are a
+set of remaining miscellaneous printable tokens that do not
 otherwise appear as [unary operators](#unary-operator-expressions), [binary
 operators](#binary-operator-expressions), or [keywords][keywords].
+They are catalogued in [the Symbols section][symbols] of the Grammar document.
+
+[symbols]: grammar.html#symbols
 
 
 ## Paths