Fix json reponse data types

[razcore-rad]

Some text editors like Helix are more strict with the json response data types. This commit updates these values:

• triggerCharacters for completion_provider, signature_help_provider
• moreTriggerCharacter for document_on_type_formatting_provider
• commands for execute_command_provider

Based on: https://microsoft.github.io/language-server-protocol/specifications/lsp/3.17/specification/#signatureHelpOptions

fixes #35

[nolanderc]

Thanks for fixing this!