Apparently this was an attempt at working around go's lack of default arguments,
but it's very unidiomatic and a bit confusing. Make it a normal parameter
instead, so all clients have to pass it explicitly.
This commit introduces a new feature to the commit view, allowing users
to filter commits based on the author's name or email address. Similar
to the existing path filtering functionality, accessible through <c-s>,
this feature allows users to filter the commit history by the currently
selected commit's author if the commit view is focused, or by typing in
the author's name or email address.
This feature adds an entry to the filtering menu, to provide users with
a familiar and intuitive experience
The only time we should call SetSelectedLineIdx is when we are happy for a
select range to be retained which means things like moving the selected line
index to top top/bottom or up/down a page as the user navigates.
But in every other case we should now call SetSelection because that will
set the selected index and cancel the range which is almost always what we
want.
