Class properties with double-underscores should not be underlined

Steps to reproduce:

1. Go to /xwiki/bin/view/XWiki/XWikiClasses
2. Create a class named "Test"
3. Add a class property to TestClass named foo__bar (note the double underscores)
4. Save and view the class

Expected results: The property should be listed as

foo__bar (foo__bar: Email)

Actual results: The property is listed as

foo<ins>bar (foo</ins>bar: Email)

See the attached screenshots.

This bug is a real problem for PhenoTips, which frequently uses double underscores in property names.