create-file-buffer is a compiled Lisp function in `
:around advice: `uniquify--create-file-buffer-advice'
Create a suitably named buffer for visiting FILENAME, and return it.
FILENAME (sans directory) is used unchanged if that name is free;
otherwise a string <2> or <3> or ... is appended to get an unused name.
Emacs treats buffers whose names begin with a space as internal buffers.
To avoid confusion when visiting a file whose name begins with a space,
this function prepends a "|" to the final result if necessary.