for commits that are reachable from r2 excluding those that are reachable
from r1 by '{caret}r1 r2' and it can be written as 'r1..r2'.
-The '...' (three dot) Symmetric Difference Notation::
+The '...' (three-dot) Symmetric Difference Notation::
A similar notation 'r1\...r2' is called symmetric difference
of 'r1' and 'r2' and is defined as
'r1 r2 --not $(git merge-base --all r1 r2)'.