Smart select default provider

[jrieken]

This is related to #4795. The plan is to delegate computation of selection ranges to extensions (#63935) but for consistent behaviour we should have good default for things that might be outside a typical syntax tree. Such as

• expand to the current full line (not just a statement) including trivia, the same for the full document
• expand ranges inside a word following camel-case rules et al
• expand string literals with/without quotation marks this cannot be done properly with token information
• simply expansion along bracket pairs
• expand bracket pairs and leading line contents