[Records] analysis server / IDE support work

[itsjustkevin]

This is the issue tracking the work that needs to be done in the analysis server to support the records feature. If you decide to work on a feature, either create an issue for the feature and link to it from here, or put your name beside the feature so that we don't duplicate effort.

• [x] Call Hierarchy (scheglov, NA)
• [x] Closing Labels (brianwilkerson, NA)
• [x] Code Completion (scheglov)
• [x] Code Folding (brianwilkerson)
• [x] documentSymbol (brianwilkerson, NA)
• [x] Flutter Outline (brianwilkerson, NA)
• [x] Hovers (brianwilkerson)
• [x] Implemented Markers (scheglov, NA)
• [x] Navigation (brianwilkerson, NA)
• [x] Occurrences (brianwilkerson, NA)
• [x] Organize Imports (scheglov, NA)
• [x] Outline (brianwilkerson)
• [x] Overrides Markers (scheglov, NA)
• [ ] #49959
• [x] Refactorings - legacy (scheglov)
• [x] Refactorings - self describing (brianwilkerson, NA)
• [x] Search - Find References (scheglov)
• [x] Search - Member Declarations (scheglov, NA)
• [x] Search - Member References (scheglov, NA)
• [x] Search - Top-level Declarations (scheglov, NA)
• [x] selectionRange (brianwilkerson)
• [x] Semantic Highlights (brianwilkerson)
• [x] signatureHelp (brianwilkerson)
• [x] Sort Members (scheglov, NA)
• [x] Type Hierarchy (scheglov, NA)