Add missing public initializers for LSP entities

[kattouf]

Hello! I noticed some issues with the library’s public API. I guess this is a consequence of the library’s past use in a mono-repo (with LanguageClient), and maybe also because some entities haven’t been used yet at all

Problem:

Some of public entities have public let properties and haven't public init constructors, that makes impossible to create and fill them outside library scope.

Solution:

I have added initializers for all the public LSP protocol entities I found (even those with var properties).

P.S.

I also ran ./run-swift-format.sh and added changes in second commit

[mattmassicotte]

Wow, thank you so much!

The reason this happened is that many LSP types only need to be created on servers. I'm aware of a few server implementations that are based on this library, and they have driven a lot of the need for initializers. But they are pretty rare compared to clients.