Update unified-style-sheet-for-linguistics.csl (#6098)

I added a IF NOT statement to the access macro so that the URL with access date is only printed if there is no DOI (which does not need an access date). This change was agreed with the author Mark Dingemanse beforehand.

Author: fussballlinguist

unified-style-sheet-for-linguistics.csl

@@ -1,5 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
 <style xmlns="http://purl.org/net/xbiblio/csl" class="in-text" version="1.0" demote-non-dropping-particle="display-and-sort" default-locale="en-US">
+  <!-- This style was edited with the Visual CSL Editor (https://editor.citationstyles.org/visualEditor/) -->
   <info>
     <title>Unified style sheet for linguistics</title>
     <id>http://www.zotero.org/styles/unified-style-sheet-for-linguistics</id>
@@ -24,9 +25,12 @@
     <contributor>
       <name>Brian Plimley</name>
     </contributor>
+    <contributor>
+      <name>Simon Meier-Vieracker</name>
+    </contributor>
     <category citation-format="author-date"/>
     <category field="linguistics"/>
-    <updated>2020-03-19T16:21:55+00:00</updated>
+    <updated>2022-06-21T14:23:09+00:00</updated>
     <rights license="http://creativecommons.org/licenses/by-sa/3.0/">This work is licensed under a Creative Commons Attribution-ShareAlike 3.0 License</rights>
   </info>
   <locale>
@@ -164,14 +168,18 @@
         </else-if>
       </choose>
       <text variable="DOI" prefix="https://doi.org/"/>
-      <text variable="URL"/>
-    </group>
-    <group prefix=" (" suffix=")">
-      <date variable="accessed">
-        <date-part name="day" suffix=" "/>
-        <date-part name="month" suffix=", "/>
-        <date-part name="year"/>
-      </date>
+      <choose>
+        <if match="none" variable="DOI">
+          <text variable="URL"/>
+          <group prefix=" (" suffix=")">
+            <date variable="accessed">
+              <date-part name="day" suffix=" "/>
+              <date-part name="month" suffix=", "/>
+              <date-part name="year"/>
+            </date>
+          </group>
+        </if>
+      </choose>
     </group>
   </macro>
   <macro name="title">