new html docs for release 4.2.1

Author: ttl-octave

docs/assets/bode_101.png

@@ -108,7 +108,7 @@
             </div>
             <div class="col-sm-9 col-md-10">
               <h3 class="d-inline-block mr-2">control</h3>
-              <b>4.2.0&nbsp;2026-01-16</b>
+              <b>4.2.1&nbsp;2026-01-20</b>
               <p class="indent">
                 Control package for GNU Octave including system analysis and  control synthesis. The package uses routines of the SLICOT-Reference library.
               </p>

docs/assets/nichols_101.png

@@ -531,7 +531,9 @@ <h3 class="d-inline-block mr-2">
 <dl>
 <dt><code><h5 class="fs">Function File: <b>rlocusx</b> (<var>sys</var>)</code></h5></dt>
 <dt><code><h5 class="fs">Function File: <b>rlocusx</b> (<var>sys</var>, <var>increment</var>, <var>min_k</var>, <var>max_k</var>)</code></h5></dt>
+<dt><code><h5 class="fs">Function File: <b>rlocusx</b> (<var>sys</var>, <var>k_vec</var>)</code></h5></dt>
 </dl>
+
 <p> Interactive root locus plot of the specified SISO system <var>SYS</var>.
 </p>
 <div class="ms-5">
@@ -610,6 +612,10 @@ <h3 class="d-inline-block mr-2">
 </dl>
 <p> Maximum value of <var>k</var>.
  </p></dd>
+<dt> <var>k_vec</var></dt>
+</dl>
+<p> Vector of values for gain values <var>k</var>.
+ </p></dd>
 </dl>
 
 <p> <strong>Outputs</strong>