bug#41890: 28.0.50; [PATCH]: Add bindings for project.el

[Juri Linkov]

>>    'C-x p d' - project dired without dispatch prompt
>>    'C-x p p d' - the same with dispatch prompt
>
> It's not the same. It asks you to select a _different_ project.

Oh, I forgot it's about switching projects.
I'm not sure how frequently this key will be used.
If not often, then better to use easier-to-type 'C-x p p'
for other more frequent commands, such as using it as
a prefix for any command to run in the project root dir,
for example, 'C-x p p M-! git pull' will run git commands
in the project root dir.