Merge tag 'doc-2026-04-rc6' of https://source.denx.de/u-boot/custodians/u-boot-efi

Pull request doc-2026-04-rc6

CI: https://source.denx.de/u-boot/custodians/u-boot-efi/-/pipelines/29687

Documentation:

* TI boards
  - fix OP-TEE args
  - fix incorrect labels for boot switches
* Fix typo in pstore documentation.
* Fix document references pointing to replaced uImage.FIT.
* buildman: Add missing :: for examples.
* overlay-fdt-boot: .dtbos do not need load addresses.
* When building the documentation use sys.path.append for pytests.