codemirror: enable matchtag addon

backport nexedi/erp5!634

This is only a partial backport, we don't have Romain's gadget in this branch

/reviewed-on https://lab.nexedi.com/nexedi/erp5-capago/merge_requests/22

bt5/erp5_code_mirror/SkinTemplateItem/portal_skins/erp5_code_mirror/code_mirror_support.txt

@@ -49,6 +49,8 @@
 <script type="text/javascript" src="&dtml-portal_url;/csslint.js"></script>
 <script type="text/javascript" src="&dtml-portal_url;/codemirror/addon/lint/css-lint.js"></script>
 <dtml-elif expr="mode == 'htmlmixed'">
+<script type="text/javascript" src="&dtml-portal_url;/codemirror/addon/fold/xml-fold.js"></script>
+<script type="text/javascript" src="&dtml-portal_url;/codemirror/addon/cm_edit/matchtags.js"></script>
 <script type="text/javascript" src="&dtml-portal_url;/codemirror/mode/xml/xml.js"></script>
 <script type="text/javascript" src="&dtml-portal_url;/codemirror/mode/javascript/javascript.js"></script>
 <script type="text/javascript" src="&dtml-portal_url;/codemirror/mode/css/css.js"></script>
@@ -513,6 +515,7 @@
                 "Ctrl-I": "indentAuto",
                 "Shift-Tab": "indentLess",
                 "Ctrl-S": function(cm){saveDocument(cm, $.Event('click'))}},
+    matchTags: {bothTags: true},
     foldGutter: true,
     lineWrapping: true,
     gutters: ["CodeMirror-lint-markers",