.bashrc.d/40 prompt: untabify
.gitconfig: various settings

* add dc alias: diff --cached
* merge.conflictstyle=diff3: diff with common ancestor
* rerere.enabled=true: reuse recorded resolution (of conflicts)
* rebase.autosquash=true
* help.autocorrect=10: autocorrect commands after 1s (if unique)
* pull.rebase=true