19876: sys/net/ipv4/addr: fix typos r=benpicco a=Enoch247
### Contribution description
This patch fixes some typos in the doxygen doc.
### Testing procedure
Nothing to test. No change to code.
### Issues/PRs references
- None known
19878: makefiles/usb_board_reset.mk: declare term-delay target with test target r=benpicco a=aabadie
19888: boards/sltb009a: complete and fix documentation r=benpicco a=gschorcht
### Contribution description
This PR completes and fixes the documentation which was still in the state as generated automatically by `efm2riot`.
The PR also includes a fix of the configuration of the second UART device that was find out while completing the documentation.
### Testing procedure
Green CI
### Issues/PRs references
Co-authored-by: Joshua DeWeese <jdeweese@primecontrols.com>
Co-authored-by: Alexandre Abadie <alexandre.abadie@inria.fr>
Co-authored-by: Gunar Schorcht <gunar@schorcht.net>
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