Fix another XMode bug

basis/xmode/code2html/code2html-tests.factor

@@ -23,3 +23,7 @@ kernel io.streams.string xml.writer ;
 [ "<span class=\"MARKUP\">: foo</span> <span class=\"MARKUP\">;</span>" ] [
     { ": foo ;" } "factor" htmlize-lines xml>string
 ] unit-test
+
+[ ":foo" ] [
+    { ":foo" } "factor" htmlize-lines xml>string
+] unit-test

basis/xmode/marker/marker.factor

@@ -84,7 +84,7 @@ M: string-matcher text-matches?
     ] keep string>> length and ;
 
 M: regexp text-matches?
-    [ >string ] dip first-match to>> ;
+    [ >string ] dip first-match dup [ to>> ] when ;
 
 : rule-start-matches? ( rule -- match-count/f )
     dup start>> tuck swap can-match-here? [