Fixup autoload regex for Emacs.

[tmcgilchrist]

Fix for #4222 the regex is not correct.

;; Original regex
;; NOTE 0 is true and nil is false (roughtly speaking)
(string-match "\\(?:\\`\\|/\\)dune\\(?:\\.inc\|-project\\)?\\'" "dune")
0
(string-match "\\(?:\\`\\|/\\)dune\\(?:\\.inc\|-project\\)?\\'" "dune.inc")
nil
(string-match "\\(?:\\`\\|/\\)dune\\(?:\\.inc\|-project\\)?\\'" "dune-project")
nil

;; New regex
(string-match "\\(?:\\`\\|/\\)dune\\(?:\\.inc\\|\\-project\\)?\\'" "dune")
0
(string-match "\\(?:\\`\\|/\\)dune\\(?:\\.inc\\|\\-project\\)?\\'" "dune.inc")
0
(string-match "\\(?:\\`\\|/\\)dune\\(?:\\.inc\\|\\-project\\)?\\'" "dune-project")
0
(string-match "\\(?:\\`\\|/\\)dune\\(?:\\.inc\\|\\-project\\)?\\'" "dune-project.inc")
nil
(string-match "\\(?:\\`\\|/\\)dune\\(?:\\.inc\\|\\-project\\)?\\'" "dune-projects")
nil

;; Potentially simplier regex from regexp-opt though I'm not sure if this covers 
;; all possible cases. I have only tested on OSX and Linux.
(regexp-opt '("dune" "dune-project" "dune.inc"))
"\\(?:dune\\(?:-project\\|\\.inc\\)?\\)"

[rgrinberg]

Thanks

[tmcgilchrist]

Cheers @rgrinberg the new version is up on MELPA.