Docs: Add description of suffix: value (#3393)

editions/tw5.com/tiddlers/filters/each.tid

@@ -6,7 +6,7 @@ type: text/vnd.tiddlywiki
 caption: each
 op-purpose: select one of each group of input titles by field
 op-input: a [[selection of titles|Title Selection]]
-op-suffix: optionally, `list-item`
+op-suffix: optionally, `list-item` or `value`
 op-parameter: the name of a [[field|TiddlerFields]], defaulting to <<.field title>>
 op-parameter-name: F
 op-output: a selection containing the first input title encountered for each distinct value of field <<.place F>>
@@ -17,6 +17,8 @@ Each input title is processed in turn. The value of field <<.place F>> in the co
 :As long as the value of the field is unique (i.e. has not been encountered before), the title is appended to the output.
 ;each:list-item
 :The value is treated as a [[title list|Title List]]. Each title in the list considered in turn. If it has not been encountered before, it is appended to the output.
+;each:value
+:As long as the title is unique it is appended to the output. Even if no such tiddler exists.
 
 If a tiddler does not contain field <<.place F>>, it is treated as if the value of the field were empty.