chg exclude subtypes für letters/ chg list to strings

gfl-plugin/src/main/resources/gfl-indexer.xslt

@@ -585,16 +585,18 @@ Refer to comments in the code to understand the used algorithm.
                <xsl:value-of select="//supportDesc/extent/dimensions/width/normalize-space()"/><xsl:text> </xsl:text><xsl:value-of select="//supportDesc/extent/dimensions/@unit/normalize-space()"/><xsl:text>, </xsl:text>
                <xsl:value-of select="//bindingDesc/normalize-space()"/>
             </field>
+            <xsl:for-each select="//handNote">
             <field name="writer">
-               <xsl:value-of select="//handNote/normalize-space()"/>
+               <xsl:value-of select="./normalize-space()"/>
             </field>
+            </xsl:for-each>
             <field name="reference">
                <xsl:value-of select="//relatedItem[@subtype = 'related']/normalize-space()"/>
             </field>
             <field name="response">
                <xsl:value-of select="//relatedItem[@subtype = 'response']/normalize-space()"/>
             </field>
-            <xsl:for-each select="//relatedItem">
+            <xsl:for-each select="//relatedItem[@type = 'letter' and not(@subtype)]">
                <field name="related_items">
                   <xsl:value-of select="./ref/normalize-space()"/>
                </field>

solr/gfl/conf/schema.xml

@@ -126,12 +126,12 @@
   <field name="entitys_in_documents" type="string" multiValued="true"/>
   
   <!-- Metadata fields -->
-  <field name="institution" type="string" multiValued="true"/>
-  <field name="shelfmark" type="string" multiValued="true"/>
-  <field name="script_source" type="string" multiValued="true"/>
+  <field name="institution" type="string" multiValued="false"/>
+  <field name="shelfmark" type="string" multiValued="false"/>
+  <field name="script_source" type="string" multiValued="false"/>
   <field name="writer" type="string" multiValued="true"/>
-  <field name="response" type="string" multiValued="true"/>
-  <field name="reference" type="string" multiValued="true"/>
+  <field name="response" type="string" multiValued="false"/>
+  <field name="reference" type="string" multiValued="false"/>
   <field name="related_items" type="string" multiValued="true"/>
 
   <field name="all_header_fields" type="text_de" multiValued="true" />