Hello,

The TAB and RET key behave differently for Git-Log-View mode and 
Outline View mode.  If TAB will consistently expand and collapse the 
bullet point on the tree and RET will consistently do across the two 
modes whatever the similar thing is, that will improve the UI.

Having consistent keybindings in modes for navigating bullet points 
on trees in general will greatly improve the UI experience.

A under Git-Log-View mode
* TAB (translated from <tab>) runs the command log-view-msg-next
* RET (translated from <return>) runs the command log-view-toggle-entry-display

B under Outline View mode
* TAB (translated from <tab>) runs the command outline-cycle
* RET (translated from <return>) runs the command View-scroll-line-forward

steps to reproduce in Git-Log-View mode
* open emacs by 'emacs -Q'
* goto emacs source directory
* apply C-x v l runs the command vc-print-log
* goto the first line with a bullet point
* goto A and perform TAB, RET

steps to reproduce in Outline View mode
* open emacs by 'emacs -Q'
* view file emacs/admin/README
* apply C-c C-t runs the command outline-hide-body
* goto the first line with a bullet point
* goto B and perform TAB, RET

observed behavior
* TAB, RET key behave differently for expanding and collapsing the bullet point in the two modes

expected behavior
* TAB, RET key behave consistently on bullet point headlines across the two modes

-- 
vl