TB after CI

• A couple WF steps (still with the incomplete WF definition though)
• some basic documentation
  • README in tree_borrows/
  • header comment in disjoint.v

assigned to @neven

enabled an automatic merge when the pipeline for 24cdff16 succeeds

aborted the automatic merge because source branch was updated

added 1 commit

• da475e3f - wrong intro pattern

Compare with previous version

enabled an automatic merge when the pipeline for da475e3f succeeds

merged

mentioned in commit d41614d7