feat(lucene): add min attribute for boolean query

see eXist-db/exist#3107

Author: duncdrum

src/main/xar-resources/data/lucene/listings/listing-1.txt

@@ -0,0 +1,4 @@
+let $query := <query><bool min="3"><term>witch</term></bool></query>
+
+return
+  //SPEECH[ft:query(LINE, $query)]        

src/main/xar-resources/data/lucene/lucene.xml

@@ -3,16 +3,15 @@
         schematypens="http://purl.oclc.org/dsdl/schematron"?><article xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink" version="5.0">
     <info>
         <title>Full Text Index</title>
-        <date>2Q19</date>
+        <date>4Q19</date>
         <keywordset>
             <keyword>indexing</keyword>
         </keywordset>
     </info>
 
     <!-- ================================================================== -->
 
-    <para>This article provides information on configuring and using eXist-db's full text
-        index.</para>
+    <para>This article provides information on configuring and using eXist-db's full text index.</para>
 
     <!-- ================================================================== -->
 
@@ -621,6 +620,8 @@
                         </variablelist>
                         <para>For instance:</para>
                         <programlisting language="xquery" xlink:href="listings/listing-41.txt"/>
+                        <para>To optimize performance you can also specify a minium number of matches to cut-off needless disjunctive searches, using the <literal>min</literal> attribute:</para>
+                        <programlisting language="xquery" xlink:href="listings/listing-1.txt"/>
                     </listitem>
                 </varlistentry>
                 <varlistentry>