Snippets in "Working with files" are not compatible with configuration cache

[mlopatkin]

Issue type

Wrong or misleading information

Problem description

• The sample uses Project.mkdir in the task's doLast action leading to configuration cache failure.
• The sample uses Project.file in the task's doLast action

Context (optional)

The code snippet is defined inline, rather than as a proper separated sample, and thus is not covered by tests.

It also has no Kotlin counterpart.

Page with the problem

https://docs.gradle.org/current/userguide/working_with_files.html#using_project_mkdir

[alllex]

This is a valid documentation issue.