Update README.md: fix definition of customName (#596)

Added escape chars to avoid the `|` in type definition being interpreted as cell separator

Author: archiloque

README.md

@@ -134,7 +134,7 @@ See [server demo](example) and [browser demo](https://github.com/bcherny/json-sc
 |-|-|-|-|
 | additionalProperties | boolean | `true` | Default value for `additionalProperties`, when it is not explicitly set |
 | bannerComment | string | `"/* eslint-disable */\n/**\n* This file was automatically generated by json-schema-to-typescript.\n* DO NOT MODIFY IT BY HAND. Instead, modify the source JSON Schema file,\n* and run json-schema-to-typescript to regenerate this file.\n*/"` | Disclaimer comment prepended to the top of each generated file |
-| customName | `(LinkedJSONSchema, string | undefined) => string | undefined` | `undefined` | Custom function to provide a type name for a given schema
+| customName | `(LinkedJSONSchema, string \| undefined) => string \| undefined` | `undefined` | Custom function to provide a type name for a given schema
 | cwd | string | `process.cwd()` | Root directory for resolving [`$ref`](https://tools.ietf.org/id/draft-pbryan-zyp-json-ref-03.html)s |
 | declareExternallyReferenced | boolean | `true` | Declare external schemas referenced via `$ref`? |
 | enableConstEnums | boolean | `true` | Prepend enums with [`const`](https://www.typescriptlang.org/docs/handbook/enums.html#computed-and-constant-members)? |