Sort key fix

Use contributor-sort macro with substitution for creator sort
key, not author variable alone.

Also, remove label from contributor-sort names node.

chicago-note-bibliography.csl

@@ -143,7 +143,6 @@
   <macro name="contributors-sort">
     <names variable="author">
       <name name-as-sort-order="all" and="text" sort-separator=", " delimiter=", " delimiter-precedes-last="always"/>
-      <label form="verb-short" prefix=", " suffix="." strip-periods="true"/>
       <substitute>
         <names variable="editor"/>
         <names variable="translator"/>
@@ -499,8 +498,8 @@
   </citation>
   <bibliography hanging-indent="true" et-al-min="11" et-al-use-first="7" subsequent-author-substitute="———" entry-spacing="0">
     <sort>
-      <key variable="author" names-min="2" names-use-first="1"/>
-      <key variable="author" names-min="11" names-use-first="7"/>
+      <key macro="contributors-sort" names-min="2" names-use-first="1"/>
+      <key macro="contributors-sort" names-min="11" names-use-first="7"/>
       <key variable="title"/>
       <key variable="genre"/>
       <key variable="issued"/>