Add quick note about accessing config through session or item objects
Add quick note about accessing config through session or item objects

Fix #5030

Akasurde/pytest,alfredodeza/pytest,The-Compiler/pytest,nicoddemus/pytest,tomviner/pytest,pytest-dev/pytest,RonnyPfannschmidt/pytest,The-Compiler/pytest,tomviner/pytest,markshao/pytest,nicoddemus/pytest