When XSD not found, just display one error

[zarathosss]

When the XSD is not found (because none defined in the XML file, or because the one which is defined cannot be accessed (wrong path for example), then there is a warning/error displayed for each tag. This is not pertinent, would rather have ONE warning/error stating that the XSD file cannot be located (or is not defined). As when using the extension "Error Lens", this makes the XML file unreadable by having a warning/error on each line.