kernel-docs need 8.2G of memory with python 3.8 now. It used to be 2.2G on
SLE15-SP2 (python 3.6). I don't have numbers for 3.7, but the build did not
fail in factory, now it fails quite often.

> [  776s] writing output... [ 55%] media/uapi/dvb/audio-continue .. media/uapi/dvb/frontend-property-terrestrial-systems
> [  783s] [  768.244238] Out of memory: Killed process 4174 (sphinx-build) total-vm:1256996kB, anon-rss:517292kB, file-rss:0kB, shmem-rss:0kB, UID:399 pgtables:2508kB oom_score_adj:0
> [  842s] writing output... [ 59%] media/uapi/dvb/frontend-stat-properties .. media/uapi/rc/lirc-set-wideband-receiver
> [  847s]
> [  847s] Exception occurred:
> [  847s]   File "/usr/lib64/python3.8/multiprocessing/connection.py", line 383, in _recv
> [  847s]     raise EOFError
> [  847s] EOFError

I indeed can increase the constraints, but 4 times larger memory footprint is
too much... This must be a bug or leak.

https://build.opensuse.org/packages/kernel-docs/job_history/Kernel:stable/standard/x86_64