new language servers and smart document highlighting

lua/lsp/html-ls.lua

@@ -0,0 +1,8 @@
+-- npm install -g vscode-html-languageserver-bin
+local capabilities = vim.lsp.protocol.make_client_capabilities()
+capabilities.textDocument.completion.completionItem.snippetSupport = true
+
+require'lspconfig'.html.setup {
+    on_attach = require'lsp'.common_on_attach,
+    capabilities = capabilities
+}