Disable/enable major modes more concisely
Use setq-default to allow buffers to set variables
Move Magit settings up (without install check)
Group global key settings
Use dolists for (slightly) improved readability
Remove unnecessary auto-mode-alist entries

yaml-mode and markdown-mode packages both add patterns to
auto-mode-alist automatically.
Show and delete trailing whitespace
Fontify Org mode code blocks