When looking up documentation with
describe-function, Emacs display the docstring in a temporary help buffer. I want this buffer to replace current window.
So far, I've customized
help-window-select but it only affect the focus.
If you don't like how help-window-select works you can simply use this code:
(add-to-list 'display-buffer-alist '("*Help*" display-buffer-same-window))
You can change
"*Help*" with a regexp matching other buffer names if you want to also affect apropos windows or shell