Merge pull request #3084 from vespa-engine/kkraune/match-features

Disable inherited match-features

en/reference/schema-reference.html

@@ -2181,6 +2181,7 @@ <h2 id="match-features">match-features</h2>
   specify explicitly that the features should be inherited from the parent as shown below,
   also see <a href="../schemas.html#schema-inheritance">schema inheritance</a>.
 </p>
+<p>To disable match-features from parent rank profiles, use <code>match-features {}</code>.</p>
 <p>
   <em>match-features</em> is similar to <a href="#summary-features">summary-features</a>,
   but the rank features specified here are computed in the <em>first phase</em> of
@@ -2538,7 +2539,7 @@ <h2 id="dictionary">dictionary</h2>
 It is primarily intended for use when you have many unique terms with few occurrences (short posting lists),
 where the dictionary lookup cost could be significant. '%}
 </p>
-  
+
 <p>
   Normally, <code>btree</code> is your best choice as it offers reasonable performance
   for both exact, prefix and range type of dictionary lookups.
@@ -2553,24 +2554,24 @@ <h2 id="dictionary">dictionary</h2>
   In addition, one can specify <code>uncased</code> or <code>cased</code> dictionary for string attributes,
   default is <code>uncased</code>.
   This setting is sanity checked against the field <a href="#match">match:casing</a> setting. </p>
-  
+
   <p>
   In an <code>uncased</code> dictionary,
   casing is normalized by lowercasing so that 'bear' equals 'Bear' equals 'BEAR'.
   In a <code>cased</code> dictionary, they will all be different.</p>
 
   <p>
 
-  Example of a string field with a cased hash dictionary. Note that for string fields with 
+  Example of a string field with a cased hash dictionary. Note that for string fields with
   dictionary type hash, the <code>dictionary</code> block must also include <code>cased</code>.
   </p>
   <pre>
 field id_str type string {
       indexing:   summary | attribute
       attribute:  fast-search
-      match:      cased	
+      match:      cased
       rank:       filter
-      dictionary { 
+      dictionary {
         hash
         cased
       }