switch to plain-module-begin, to avoid redundant extra outputs

svn: r11556

original commit: 0ccfb6f8b4e7fc1b2caa375467a3cba8b14d93ab

collects/scribble/text/textlang.ss

@@ -96,4 +96,4 @@
     [(_ expr ...)
      ;; add a dummy define and throw it away, to get rid of initial newlines
      (with-syntax ([(_ expr ...) (process-body #'((define) expr ...))])
-       #'(#%module-begin expr ...))]))
+       #'(#%plain-module-begin expr ...))]))