[XML] Fix folding of tags with fully qualified names

This commit fixes an issue, which confused syntax based folding, if fully
qualified tag names are involved.

```xml
<?xml version="1.0" encoding="UTF-8"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema">
    <xs:element name="Data">
        <xs:complexType>
            <xs:sequence>
                <!--Allowing arbitrary element names-->
                <xs:any maxOccurs="unbounded" processContents="lax"/>
            </xs:sequence>
            <!--Element names must be unique-->
            <xs:assert test="every $child in * satisfies not($child/preceding::*[name() = name($child)])"></xs:assert>
        </xs:complexType>
    </xs:element>
</xs:schema>
```

XML/Fold.tmPreferences

@@ -87,7 +87,7 @@
                 Note: Works only if closing punctuation is already on a separate line.
                 -->
                 <key>begin</key>
-                <string>meta.tag entity.name.tag</string>
+                <string>meta.tag entity.name.tag.localname</string>
                 <key>end</key>
                 <string>meta.tag punctuation.definition.tag</string>
                 <key>excludeTrailingNewlines</key>