v1.5.0: Introducing the history log buffer

Add the history log buffer(gl from the branch list), which allows:

• Viewing the commit history of a branch
• Viewing information on each commit
• Checking out commits
• Diffing against commits

Other changes:

• Add pr keymap for pull --rebase
• Add q keymap for closing the side-buffers
• Minor typo fixes and output/doc styling changes