[docs] deprecated CIDER variable used for Editor > Emacs example

[Practicalli Johnny]

Update required on: https://cljdoc.org/d/djblue/portal/0.37.1/doc/editors/emacs

The CIDER variable cider-clojure-cli-global-options has been deprecated for quite a while and replaced by cider-clojure-cli-aliases variable

Reference:

• clojure-emacs/cider#2941 - new CIDER variable
• https://docs.cider.mx/cider/basics/up_and_running.html#clojure-cli-options (current docs)

The example in the Editor > Emacs page is not guaranteed to work with stable CIDER version

(setq cider-clojure-cli-global-options "-A:portal")

The above should be replaced by

(setq cider-clojure-cli-aliases ":portal")

The execution flag is not required and any flag given is stripped from the alias name by the CIDER jack-in command

NOTE: Code to add portal related commands to Spacemacs can also be submitted if desired