Add default usage of shell custom commands again based on filename, fixes #2633 (#2635)
Add default usage of shell custom commands again based on filename, fixes #2633 (#2635)

Was accidentally removed with https://github.com/drud/ddev/commit/c34907d7d6cd836e0571ad0b0effcaa1d48a7b83
rfay/ddev,rfay/ddev,drud/ddev,rfay/ddev,drud/ddev,rfay/ddev,drud/ddev,rfay/ddev,drud/ddev,drud/ddev