Part 1: smallest typo yet, just an extra space.
Step 1: #35.20
added test for staticmenulinkoverride
Part 1: typo: menusor -> menus or.
reformat interface comment
START PART 2:  https://www.drupal.org/node/2301273
apply patch https://www.drupal.org/files/issues/menu-2256521-MenuLinkTree-review-do-not-test.patch
convert createLink to addDefinition
docs fixes suggested by dawehner
Fix t() to $this->t()
some dawehner fixes
reapply review #15
some doc fixes
Part 2: 2301723 Added namespace in MenuParentFormSelector.php