ox-texinfo: Export example blocks as @example

* lisp/ox-texinfo.el (org-texinfo-example-block): Export as @example.

Escape @, {, }, however, so as to get proper verbatim contents.

etc/ORG-NEWS

@@ -360,11 +360,9 @@ is now obselete.
 
 Now ~=...=~ markup uses ~@samp{}~ instead of ~@verb{}~.  You can use
 ~@verb{}~ again by customizing the variable.
+*** Texinfo exports example blocks as ~@example~
 *** Texinfo exports inline src blocks as ~@code{}~
 
-It is possible to write an inline src block filter to use ~@verb{}~
-again.
-
 * Version 9.0
 
 ** Incompatible changes

lisp/ox-texinfo.el

@@ -778,8 +778,9 @@ holding contextual information."
   "Transcode an EXAMPLE-BLOCK element from Org to Texinfo.
 CONTENTS is nil.  INFO is a plist holding contextual
 information."
-  (format "@verbatim\n%s@end verbatim"
-	  (org-export-format-code-default example-block info)))
+  (format "@example\n%s@end example"
+	  (org-texinfo--sanitize-content
+	   (org-export-format-code-default example-block info))))
 
 ;;; Export Block