message: Add docs on multiline string literals to readme
diff: @@ -165,6 +165,8 @@ OPTIONS
  --queries=queries Deprecated in favor of the includes flag
  + --suppressSwiftMultilineStringLiterals Prevents operations from being rendered as multiline strings [Swift only]
  +
  --tagName=tagName Name of the template literal tag used to identify template literals
  containing GraphQL queries in Javascript/Typescript code
  