Emmet extension for expansion and all other actions using the new apis

[ramya-rao-a]

For April Milestone:

Emmet features are now modularized in https://www.npmjs.com/%7Eemmetio
For example: https://github.com/emmetio/expand-abbreviation is a stand alone module for the Expand Abbreviation feature from emmet.

This issue is to track the below emmet features in a VSCode extension using the new APIs and is essentially emmet 2.0

• Get emmet expansions in auto-complete suggestion list
• Wrap with Abbreviation
• Remove Tag
• Update Tag
• Go to Matching Pair

For May Milestone

• Balance Inward
• Balance Outward
• Split/Join Tags
• Merge Lines
• Toggle Block Comment (html)
• Toggle Block Comment (stylesheet)
• Go to Next/Previous edit point
• Select Next/Previous item (html)
• Select Next/Previous item (stylesheet)

Deferred to next Milestone

• Increment/Decrement by n
• Update Image Size
• Evaluate Math Expression
• Reflect CSS Value

[ramya-rao-a]

Initial commit: https://github.com/ramya-rao-a/vscode-emmet

[ramya-rao-a]

At the end of April milestone, the extension is ready for testing, but not yet published.

Currently available features are listed in the README

[ramya-rao-a]

At the end of May milestone, the below are the emmet actions not yet implemented using the new emmet modules

• Increment/Decrement by n
• Update Image Size
• Evaluate Math Expression
• Reflect CSS Value

emmet.useModules is the setting which when set to true uses the built in emmet extension (which uses the new emmet modules and gives emmet expansions in auto complete suggestions) instead of the current built in emmet

[sergeche]

Reflect CSS Value action won’t be implemented in Emmet 2. I plan to create a separate feature/plugin for automatic mapping and updating vendor-prefixed properties as user types.

[ramya-rao-a]

Thanks for the update @sergeche

Created #27697 for the remaining 3 emmet actions.