[css-syntax-3][editorial] Link to the algo in question.

Author: tabatkins

css-syntax-3/Overview.bs

@@ -3447,7 +3447,7 @@ Defining Grammars for Rules and Other Values</h2>
 Defining Block Contents: the <<block-contents>>, <<declaration-list>>, <<qualified-rule-list>>, <<declaration-rule-list>>, and <<rule-list>> productions</h3>
 
 	The CSS parser is agnostic as to the contents of blocks--
-	they're all parsed with the same algorithm,
+	they're all [=consume a block's contents|parsed with the same algorithm=],
 	and differentiate themselves solely by what constructs are valid.
 
 	When writing a rule grammar,