Document recommended way to limit size of breadcrumbs

[alexbjorlig]

In our project we have some large queries and mutations.

What is the recommended way to limit the size of the queries/variables --> using the transform fn?

Do you like an idea of a PR adding a option to specify a limit for the query/variables length - and then truncate if above?

Let me know what you think.

[spawnia]

Open for improvements to the API or the docs.