doc update

scribblings/decode.scrbl

@@ -41,7 +41,7 @@ Recursively process a @racket[_tagged-xexpr], usually the one exported from a Po
 
 This function doesn't do much on its own. Rather, it provides the hooks upon which harder-working functions can be hung. 
 
-Recall from [future link: Pollen mechanics] that any tag can have a function attached to it. By default, the @racket[_tagged-xexpr] from a source file is tagged with @racket[root]. So the typical way to use @racket[decode] is to attach your decoding functions to it, and then define @racket[root] to invoke your @racket[decode] function. Then it will be automatically applied to every @racket[doc] during compile. 
+Recall that in Pollen, all @secref["tags-are-functions"]. By default, the @racket[_tagged-xexpr] from a source file is tagged with @racket[root]. So the typical way to use @racket[decode] is to attach your decoding functions to it, and then define @racket[root] to invoke your @racket[decode] function. Then it will be automatically applied to every @racket[doc] during compile. 
 
 For instance, here's how @racket[decode] is attached to @racket[root] in @italic{Butterick's Practical Typography}. There's not much to it —
 

scribblings/tutorial-third.scrbl

@@ -341,7 +341,7 @@ And most important:
 
  As we'll see in the next section, this is where your book truly becomes programmable.
 
-@section{Tags are functions}
+@section[#:tag "tags-are-functions"]{Tags are functions}
 
 @(noskip-note)