doc(TODO): remove separator parameter

TODO.org

@@ -489,40 +489,41 @@ Macro creates -
 Currently we have at least three ways of displaying durations - ="HH:MM:SS"= , ="XhYm"= , and =X hour(s), Y minutes(s)"= . Make a single function similar to =format-time-string=, but for durations. =ts-human-format-duration= from =ts.el= is not nearly as flexible as I'd like. When completed, we can have a single custom variable accepting a format string, which can be used to customize display of durations for the entire application with a uniform interface.
 
 ** spec
-User provides a duration (in seconds), a format string, and an optional separator string.
-+ format string - ="<escape character>[<zero value><separator>]<code>"=
+User provides a format string and a duration (in seconds).
++ /format string/ is a mix of /unit specifiers/ and /unit separators/
++ a /unit specifier/ is ="<escape character>[<zero value><value separator>]<code>"=
   * escape character can be either
     - =~= - no unit strings, e.g.
-      #+BEGIN_SRC emacs-lisp :tangle no :load no
-(format-duration "~ss" 1)         ;; => "1s"
+      #+BEGIN_SRC emacs-lisp
+        (format-duration "~ss" 1)         ;; => "1s"
       #+END_SRC
       or
     - =%= long unit strings, e.g. "minute". If the value is >1, plurals are used.
-      #+BEGIN_SRC emacs-lisp :tangle no :load no
-(format-duration "%s" 1)          ;; => "1 second"
-(format-duration "%s" 5)          ;; => "5 seconds"
-(format-duration "%m%s" 5)        ;; => "5 seconds"
-(format-duration "%m%s" 60)       ;; => "1 minute"
-(format-duration "%m%s" 125)      ;; => "2 minutes 5 seconds"
+      #+BEGIN_SRC emacs-lisp
+        (format-duration "%s" 1)          ;; => "1 second"
+        (format-duration "%s" 5)          ;; => "5 seconds"
       #+END_SRC
   * zero value - what to do when the unit has a value of 0
     + with no unit strings
-      - if omitted, print =""= and omit any text in the format string until the next escape character is encountered
+      - if omitted, print =""= and omit the following unit separator, i.e. any text in the format string until the next escape character is encountered
       - if =0=, print ="0"=
     + with long unit strings
-      - if omitted, print =""= for a unit which has a value of 0, e.g. ="3 months"=
+      - if omitted, print =""= for a unit which has a value of 0
+        #+BEGIN_SRC emacs-lisp
+          (format-duration "%m %s" 5)       ;; => "5 seconds"
+          (format-duration "%m %s" 60)      ;; => "1 minute"
+          (format-duration "%m %s" 125)     ;; => "2 minutes 5 seconds"
+        #+END_SRC
       - if =0=, print ="0 <units>"=, e.g. ="0 years, 3 months"=
-  * separator is
+  * value separator is
     - used between value and unit, i.e. only applicable with =%= escape character
-    - only used when there is a value present to the left
     - if unspecified, it is a space (?)
   * codes -
     - large units are capitals - =Y= (years), =M= (months), =W= (weeks), =D= (days)
     - small units are lower-case - =h= (hours), =m= (minutes), =s= (seconds)
-  * if the value is 0, the value and the unit are ignored even if provided in the input string
-+ optional separator string (=" "= if not provided) is interspersed between each value+unit combination, e.g.
-  #+BEGIN_SRC emacs-lisp :tangle no :load no
-(format-duration "%m%s" 61 ", ")        ;; => "1 minute, 1 second"
++ a /unit separator/ is any text between two unit specifiers.
+  #+BEGIN_SRC emacs-lisp
+    (format-duration "%m, %s" 61)        ;; => "1 minute, 1 second"
   #+END_SRC
 
 Special cases