* checker.ts: Remove null check on symbols
* tsserverProjectSystem.ts: add two tests
* client.ts, completions.ts, types.ts: Add codeActions member to CompletionEntryDetails
* protocol.ts, session.ts: Add codeActions member to CompletionEntryDetails protocol
* protocol.ts, session.ts, types.ts: add hasAction to CompletionEntry
* session.ts, services.ts, types.ts: Add formattingOptions parameter to getCompletionEntryDetails
* completions.ts: define SymbolOriginInfo type
* completions.ts, services.ts: Add allSourceFiles parameter to getCompletionsAtPosition
* completions.ts, services.ts: Plumb allSourceFiles into new function getSymbolsFromOtherSourceFileExports inside getCompletionData
* completions.ts: add symbolToOriginInfoMap parameter to getCompletionEntriesFromSymbols and to return value of getCompletionData
* utilities.ts: Add getOtherModuleSymbols, getUniqueSymbolIdAsString, getUniqueSymbolId
* completions.ts: Set CompletionEntry.hasAction when symbol is found in symbolToOriginInfoMap (meaning there's an import action)
* completions.ts: Populate list with possible exports (implement getSymbolsFromOtherSourceFileExports)
* completions.ts, services.ts: Plumb host and rulesProvider into getCompletionEntryDetails
* completions.ts: Add TODO comment
* importFixes.ts: Add types ImportDeclarationMap and ImportCodeFixContext
* Move getImportDeclarations into getCodeActionForImport, immediately after the implementation
* importFixes.ts: Move createChangeTracker into getCodeActionForImport, immediately after getImportDeclarations
* importFixes.ts: Add convertToImportCodeFixContext function and reference it from the getCodeActions lambda
* importFixes.ts: Add context: ImportCodeFixContext parameter to getCodeActionForImport, update call sites, destructure it, use compilerOptions in getModuleSpecifierForNewImport
* importFixes.ts: Remove moduleSymbol parameter from getImportDeclarations and use the ambient one
* importFixes.ts: Use cachedImportDeclarations from context in getCodeActionForImport
* importFixes.ts: Move createCodeAction out, immediately above convertToImportCodeFixContext
* Move the declaration for lastImportDeclaration out of the getCodeActions lambda into getCodeActionForImport
* importFixes.ts: Use symbolToken in getCodeActionForImport
* importFixes.ts: Remove useCaseSensitiveFileNames altogether from getCodeActions lambda
* importFixes.ts: Remove local getUniqueSymbolId function and add checker parameter to calls to it
* importFixes.ts: Move getCodeActionForImport out into an export, immediately below convertToImportCodeFixContext
* completions.ts: In getCompletionEntryDetails, if there's symbolOriginInfo, call getCodeActionForImport
* importFixes.ts: Create and use importFixContext within getCodeActions lambda
* importFixes.ts: Use local newLineCharacter instead of context.newLineCharacter in getCodeActionForImport
* importFixes.ts: Use local host instead of context.host in getCodeActionForImport
* importFixes.ts: Remove dummy getCanonicalFileName line
* Filter symbols after gathering exports instead of before
* Lint
* Test, fix bugs, refactor
* Suggestions from code review
* Update api baseline
* Fix bug if previousToken is not an Identifier
* Replace `startsWith` with `stringContainsCharactersInOrder`
* Don't count a write-only reference as a use
* Split isWriteAccess to isWriteOnlyAccess and isReadOnlyAccess
* Update "unusedParameterUsedInTypeOf" to use "b"
* Update diagnostic messages: "is never used" -> "its value is never read"
* Use a WriteKind enum
* Rename enum and move documentation to enum members
