fix reference hyphen and some abbreviations

original commit: 8f23d9dc1a281433982dd3a27cee263983911c62

collects/scribble/private/manual-style.rkt

@@ -52,7 +52,7 @@
 (provide/contract
  [PLaneT element?]
  [hash-lang (-> element?)]
- [etc string?]
+ [etc element?]
  [inset-flow (() () #:rest (listof pre-content?) . ->* . any/c)] ; XXX no docs and bad return contract
  [litchar (() () #:rest (listof string?) . ->* . element?)]
  [t (() () #:rest (listof pre-content?) . ->* . paragraph?)]
@@ -61,7 +61,7 @@
 
 (define PLaneT (make-element "planetName" '("PLaneT")))
 
-(define etc "etc.") ; so we can fix the latex space, one day
+(define etc (make-element #f (list "etc" ._)))
 
 (define (litchar . strs)
   (let ([s (string-append* (map (lambda (s) (regexp-replace* "\n" s " "))

collects/scribblings/scribble/manual.scrbl

@@ -1233,6 +1233,9 @@ Returns @racket[#t] if @racket[v] is a bibliography entry created by
 @defproc[(t [pre-content pre-content?] ...) paragraph?]{Wraps the
 @tech{decode}d @racket[pre-content] as a paragraph.}
 
+@defthing[etc element?]{Like @racket["etc."], but with an
+abbreviation-ending period for use in the middle of a sentence.}
+
 @defthing[PLaneT element?]{@racket["PLaneT"] (to help make sure you get
 the letters in the right case).}