converted a bunch of tex-isms to scribble-isms and other small improvements in the docs

svn: r9760

original commit: 694a0d732be8c71fa5d4c421ac3316b2875cea38

collects/scribble/srcdoc.ss

@@ -6,6 +6,7 @@
 
 (provide require/doc
          provide/doc
+         thing-doc
          parameter-doc
          proc-doc
          proc-doc/names)
@@ -205,3 +206,19 @@
           #'(defparam id arg-id contract . desc)
           #'(scribble/manual)
           #'id))])))
+
+(define-provide/doc-transformer thing-doc
+  (lambda (stx)
+    (syntax-case stx ()
+      [(_ id contract desc)
+       (begin
+         (unless (identifier? #'id)
+           (raise-syntax-error 'parameter/doc 
+                               "expected an identifier"
+                               stx
+                               #'id))
+         (values
+          #'[id contract]
+          #'(defthing id contract . desc)
+          #'(scribble/manual)
+          #'id))])))