[utils] Add the possibility to add elements in the head of an UStringIO list
Document: cubicweb-docTitle: CubicWeb DocumentationAuthor: LogilabAbstract: Some base documentation for CubicWeb users and developersSection: ProgrammingFormat: HTMLIndex: /usr/share/doc/python-cubicweb-documentation/html/index.htmlFiles: /usr/share/doc/python-cubicweb-documentation/html/*