src: Allow `ga` to skip removed buffers

This commit prevents `ga` from returning a “no last buffer” error
when the previously displayed buffer was removed.

Since the jumps list keeps track of the order in which buffers were
displayed already, handling arbitrary `delete-buffer`s as well,
cycle through it to implement `ga` instead of storing a pointer.

Note that this commit doesn't take into account buffer flags that
might exclude some buffers from being cycled over by commands.

Fixes #1840

0 files changed, 0 insertions, 0 deletions