doc: add suggestion to use --3way
The CI seems to do a 3way merge so it is possible that even though the CI passed, the existing git am command may fail. Add text to suggest how to handle this by adding the --3way option.
Checklist
-
make -j4 test
(UNIX), orvcbuild test
(Windows) passes -
documentation is changed or added -
commit message follows commit guidelines
Affected core subsystem(s)
doc