add json format

lua/lsp/efm.lua

@@ -2,13 +2,18 @@
 -- https://github.com/mattn/efm-langserver
 return {
 	init_options = { documentFormatting = true },
-	filetypes = {'python'},
+	filetypes = { 'python', 'json' },
 	settings = {
 		rootMarkers = { ".git/" },
 		languages = {
 			python = {
 				-- pip install yapf
 				{ formatCommand = "yapf --quiet", formatStdin = true }
+			},
+			json = {
+				-- yarn global add fixjson
+				{ formatCommand = "fixjson", formatStdin = true }
+
 			}
 		}
 	}