doc/go1.17: mention new encoding/csv/Reader.FieldPos method

For #44221
For #44513

Change-Id: I2d2d1c55255f4411c11fd51f0f3ae726cbf4d136
Reviewed-on: https://go-review.googlesource.com/c/go/+/323349
Trust: Ian Lance Taylor <[email protected]>
Reviewed-by: roger peppe <[email protected]>

Author: ianlancetaylor

doc/go1.17.html

@@ -393,6 +393,18 @@ <h3 id="minor_library_changes">Minor changes to the library</h3>
   </dd>
 </dl><!-- encoding/binary -->
 
+<dl id="encoding/csv"><dt><a href="/pkg/encoding/csv/">encoding/csv</a></dt>
+  <dd>
+    <p><!-- CL 291290 -->
+      The new
+      <a href="/pkg/encoding/csv/#Reader.FieldPos"><code>Reader.FieldPos</code></a>
+      method returns the line and column corresponding to the start of
+      a given field in the record most recently returned by
+      <a href="/pkg/encoding/csv/#Reader.Read"><code>Read</code></a>.
+    </p>
+  </dd>
+</dl><!-- encoding/csv -->
+
 <dl id="flag"><dt><a href="/pkg/flag/">flag</a></dt>
   <dd>
     <p><!-- CL 271788 -->