* use callbag to implement document format with timeout
* document lsp#stream() with example
* send message to stream when using lsp#_new_command
* use -- for args parsing and add g:lsp_document_format_sync_timeout
* throw string exception
* use new func for <plug>(lsp-document-format)
* document g:lsp_format_sync_timeout
* rename to document_formatting
* add document_range_formatting.vim
* remove formatting from ui/vim.vim
* document :LspDocumentRangeFormatSync
* add LspDocumentFormatSync example in README.md