Sets an attribute to the specified element.
If the attribute is a known attribute, the value of the attribute is set.
If the attribute is an extended attribute, the 'openxmlAttribute' is added to the extended attributes list.
Namespace:DocumentFormat.OpenXml Assembly: DocumentFormat.OpenXml (in DocumentFormat.OpenXml.dll) Version: 2.11.3+Branch.master.Sha.3fcdea311b5a001803ff150de35c25fd4cd62f93.3fcdea311b5a001803ff150de35c25fd4cd62f93