First of all, thanks for the amazing project! I've been using it pretty frequently for the last few months and found it extremely useful!

Currently, TexLab supports completions with unicode (and image, even though I am not able to use it currently) previews (please see the first dropdown) and supports textDocument/hover on labels and citations (please see the second dropdown). However, I don't think it currently supports textDocument/hover to preview, say \pi, \theta, or \leftarrow. I think it might be a good idea to add unicode preview when called hover on these commands/macros and documentation where applicable.

Example completion for \pi

textDocument/hover on an example label

require('lspconfig').texlab.setup {
	on_attach = on_attach,
	capabilities = capabilities,
	filetypes = { "tex", "plaintex", "bib" },
	cmd = { "texlab" },
	settings = {
		texlab = {
			latexindent = {
				['local'] = vim.fn.getcwd() .. '/indentconfig.yaml',
			}
		}
	}
}