Use xsd:annotation to show hover and Go To Definition command

[nlips]

Three suggested features (inspired by Visual Studio XML editor) :

• Show a tooltip when the mouse is over an element name or attribute name. This tooltip show the documentation provided by the element in the schema.
• Show the same documentation into the auto complete list
• Add a "Go to definition" in the context menu

[rogalmic]

Comments:

1. Tooltip -> seems nice, will check it.
2. Autocomplete should already show xsd:annotation info.
3. Go to definition -> does it mean showing xsd file? Seems like cool idea.

I will need to find some time for this :)

[rogalmic]

Build wit initial hover support ready for testing: https://github.com/rogalmic/vscode-xml-complete/releases/tag/untagged-349ddfa84a2e34808da8

[rogalmic]

And test version for "go to definition": https://github.com/rogalmic/vscode-xml-complete/releases/tag/untagged-8d43eeff125ef6d88650

[rogalmic]

Implemented...