Improve XML references pattern

[angelozerr]

Today XML references uses pattern to know if expressions must be applied for a given XML file.

"xml.references": [
    {
      "pattern": "**/docbook.xml",
      "expressions": [
        {
          "from": "xref/@linkend",
          "to": "@id"
        }
      ]
    }
  ]

Those references will be applied for all XML document which matches the pattern **/docbook.xml

Instead of providing only pattern It should be nice if we could add more filter like:

• apply for xsd, apply for rng, etc

"xml.references": [
    {
      "applyFor": "xsd",
   }
  ]

• defines URIs of some grammar file ex : *tei.xsd

"xml.references": [
    {
      "whenBoundWithGrammar": "**/tei.xsd",
   }
  ]

• defines include element (ex : xs:include/@href xs:import/@href for xsd)

"xml.references": [
    {
      "applyFor": "xsd",
      "include": ["xs:include/@href", "xs:import@href"],
      "expressions": [
             {
               "from": "element/@type",
               "to": "complexType/@name"
             }
        ]
     }
  ]

It should be nice too to contribute to XML references plugin with a plugin. The goal is to use XML references to manage references for xs:completxType/@name for XSD and define/@name for rng which are managed todaywith scpecific code.

As XML references is superiror to custom code which manages XSD and RNG, those files should use XML references support.

In other words, XSD plugin will be able to register this XML references

"xml.references": [
    {
      "applyFor": "xsd",
      "include": ["xs:include/@href", "xs:import@href"],
   }
  ]

And all features for XSD:

• https://github.com/redhat-developer/vscode-xml/blob/main/docs/Features/XSDFeatures.md#codelens-support
• https://github.com/redhat-developer/vscode-xml/blob/main/docs/Features/XSDFeatures.md#xsd-tag-support

will be managed by XML references support and we will able to to remove all code specific for XSD which manages that (very nice for maintenance)