HTML path refactor

[octref]

Changes include

• Refactored tests to test path completion in a more end-to-end way (checking `resultText')
• Enhanced test suite to cover empty path, completion inside middle of path, remote path, etc
• Support path completion in the middle of path until next whitespace. path completion: support code completion inside an existing path until next whitespace #44814
• restart option so reloading the development instance of the client/server setup would reconnect both client and server. Although it's default to true it does not work now (See restart should defaults to false in accordance with its behavior #45602)