Simplify .editorconfig & .prettierrc.json (DefinitelyTyped#37400)

* Simplify .editorconfig & .prettierrc.json

* Update `"trailingComma"` to `"all"`. Remove md indent_size

Author: demensky

.editorconfig

@@ -4,7 +4,5 @@ root = true
 indent_size = 4
 trim_trailing_whitespace = true
 insert_final_newline = true
-
-[{*.json,*.yml,*.ts,*.tsx,*.md}]
+max_line_length = 120
 indent_style = space
-

.prettierrc.json

@@ -1,20 +1,6 @@
 {
     "$schema": "http://json.schemastore.org/prettierrc",
-
-    "parser": "typescript",
-    "printWidth": 120,
-    "semi": true,
     "singleQuote": true,
-    "tabWidth": 4,
-    "trailingComma": "es5",
-
-    "overrides": [
-        {
-            "files": ["*.md"],
-            "options": {
-                "tabWidth": 2
-            }
-        }
-    ]
+    "trailingComma": "all"
 }