JATS template: fix incomplete previous commit

data/templates/article.jats_publishing

@@ -208,3 +208,4 @@ $back$
 $endif$
 </back>
 </article>
+

data/templates/default.jats_articleauthoring

@@ -19,7 +19,7 @@ $endif$
 $if(author)$
 <contrib-group>
 $for(author)$
-<contrib contrib-type="author"$if(author.equal-contrib)$ equal-contrib="true"$endif$>
+<contrib contrib-type="author"$if(author.equal-contrib)$ equal-contrib="yes"$endif$>
 $if(author.orcid)$
 <contrib-id contrib-id-type="orcid">$author.orcid$</contrib-id>
 $endif$

doc/jats.md

@@ -53,9 +53,9 @@ Metadata Values
     `equal-contrib`
     :   boolean attribute used to mark authors who contributed
         equally to the work. The
-        [`equal-contrib`][attr:equal-contrib] attribute is added
-        to the author's [`<contrib>`] element if this is set to a
-        truthy value.
+        [`equal-contrib`][attr:equal-contrib] attribute, set to
+        `yes`, is added to the author's [`<contrib>`] element if
+        this is set to a truthy value.
 
     `cor-id`
     :   identifier linking to the contributor's correspondence