feat: better slugify function

The new version can now find anything that isn't considered an
alphanumeric character and replace it with appropriate dashes.  We
also clean up repeated dashes and trim dashes from both start and end
of the string.

t/weblorg-tests.el

@@ -26,6 +26,10 @@
 (require 'cl-lib)
 (require 'weblorg)
 
+(ert-deftest weblorg--slugify ()
+  (should (equal (weblorg--slugify "!v0.1.1 - We've come a long way, friend!")
+                 "v0-1-1-we-ve-come-a-long-way-friend")))
+
 (ert-deftest weblorg--collect-n-aggr ()
   (weblorg-route
    :base-dir (expand-file-name "t/fixtures/test1/" default-directory)

weblorg.el

@@ -955,11 +955,7 @@ be added ad an entry to the returned assoc."
        ;; Don't override existing value, so users can still put
        ;; whatever they want
        (unless (org-element-property :CUSTOM_ID headline)
-         (let ((headline-slug
-                (weblorg--slugify
-                 ;; Add ".0" suffix because weblorg--slugify strips
-                 ;; away the file extension
-                 (format "%s.0" (org-element-property :raw-value headline)))))
+         (let ((headline-slug (weblorg--slugify (org-element-property :raw-value headline))))
            (org-element-put-property headline :CUSTOM_ID headline-slug)))
        ;; Replace these IDs that don't have much use within weblorg. That
        ;; will cause way less noise when re-generating a project without
@@ -1023,10 +1019,24 @@ expression (not a glob)."
           result))))))
 
 (defun weblorg--slugify (s)
-  "Make slug of S."
+  "Make slug of S.
+
+It replaces anything that isn't between a-z and 0-9 with dashes
+return the lower case version of the string.  e.g.:
+
+#+BEGIN_SRC emacs-lisp
+  (weblorg--slugify \"We've come a long way, friend!\")
+  \"we-ve-come-a-long-way-friend\"
+#+END_SRC"
   (downcase
-   (replace-regexp-in-string
-    "\s" "-" (file-name-sans-extension (file-name-nondirectory s)))))
+   (seq-reduce
+    (lambda(accum item)
+      (replace-regexp-in-string (car item) (cdr item)  accum))
+    '(("[^[:alnum:]]" . "-")
+      ("--+"          . "-")
+      ("^-"           . "")
+      ("-$"           . ""))
+    s)))
 
 (defun weblorg--get (seq item &optional default)
   "Pick ITEM from SEQ or return DEFAULT from list of cons."