Indentation improvements

[isidorn]

Assignees:

• Windows @gregvanl
• OS X @bpasero
• Linux @joaomoreno

We have improved our indentation support. Verify:

New defaults

• By default we ship with editor.detectIndentation = true, editor.tabSize = 4, editor.insertSpaces = false.
• When editor.detectIndentation is set to true, and the file has sufficient hints (it is not empty, it has indented content), editor.tabSize and editor.insertSpaces will be guessed from the file contents.
• Since the detection code now kicks in by default, please open some files from other OSS projects and check if the indentation is guessed correctly.
• Migration story: Make sure you get a warning and a notification message if either editor.tabSize, editor.inserSpaces are set to 'auto' and a custom hover message on the values in settings.

Note: By design, editor.tabSize will be guessed only to 2, 4, 6 or 8.

Status Bar

• Status bar always shows indentation status and clicking on it shows indentation actions
• 'Detect indentation from Content' guesses the indentation in the current editor from the content
• All the configured indentation is preserved in a vscode session for a file - if you open the same file in a new editor it should have the same indentation settings

[isidorn]

@alexandrudima please update this test plan item as you see fit