fix missing syntax highlighting on auto-insert

Author: garfieldnate

src/main/java/edu/umich/soar/visualsoar/ruleeditor/RuleEditor.java

@@ -1792,6 +1792,7 @@ private void complete(int pos, String userType, List<String> completeMatches) {
     if (completeMatches.size() == 1) {
       String matched = completeMatches.get(0);
       EditingUtils.insert(editorPane.getDocument(), matched.substring(userType.length()), pos);
+      editorPane.colorSyntax();
       return;
     }