Always add the family name from spacing=100

conf.d/48-spacing.conf

 <?xml version="1.0"?>
 <!DOCTYPE fontconfig SYSTEM "urn:fontconfig:fonts.dtd">
 <fontconfig>
-  <description>Add mono to the family when no generic name and spacing is 100</description>
+  <description>Add mono to the family when spacing is 100</description>
 <!--
-  If the font has no generic name and spacing 100, add mono
+  If the request specifies spacing 100, add monospace to family
  -->
 	<match target="pattern">
-		<test qual="all" name="family" compare="not_eq">
-			<string>sans-serif</string>
-		</test>
-		<test qual="all" name="family" compare="not_eq">
-			<string>serif</string>
-		</test>
-		<test qual="all" name="family" compare="not_eq">
-			<string>monospace</string>
-		</test>
 		<test qual="any" name="spacing" compare="eq">
 			<int>100</int>
 		</test>
-		<edit name="family" mode="append_last">
+		<edit name="family" mode="prepend">
 			<string>monospace</string>
 		</edit>
 	</match>