* upstream/master: (143 commits)
  Use Unicode for OutputEncoding (dotnet#49721)
  Fix tests
  Remove unnecessary parens when converting switch statement ot expression.
  Fix flaky test
  Simplify implementation of IsOrInGenericType helper and reduce code duplication. (dotnet#49763)
  Increase CoreCLR dump information
  NRT
  Be resilient to a null-document in the code-folding service.
  Change cache implementation from dictionary to list
  Fix APIs for retrieving solution snapshot from Razor, UT (dotnet#49591)
  Handles optional parameters
  Feature/disambiguate using keyword (dotnet#48898)
  Check all overloads when inferring first argument in an invocation with nothing typed
  Remove optional parameter
  lint
  Clean up option handling
  Remove double blank line
  Add + update tests
  Ensure completion and completion resolve handler always pass the same options
  Change name of telemetry
  ...