updated docs

Author: ttl-octave

docs/@lti_pole.html

@@ -98,7 +98,7 @@ <h3 class="d-inline-block mr-2">
  For <acronym>SISO</acronym> transfer functions, <code>pole</code>
  uses Octave&rsquo;s <code>roots</code>.
  <acronym>MIMO</acronym> transfer functions are converted to
- a <em>minimal</em> state-space representation for the
+ a <math>minimal</math> state-space representation for the
  computation of the poles.
 </p>
 

docs/@lti_zero.html

@@ -182,7 +182,7 @@ <h3 class="d-inline-block mr-2">
  For <acronym>SISO</acronym> transfer functions, <code>zero</code>
  uses Octave&rsquo;s <code>roots</code>.
  <acronym>MIMO</acronym> transfer functions are converted to
- a <em>minimal</em> state-space representation for the
+ a <math>minimal</math> state-space representation for the
  computation of the zeros.
 </p>
 <p> <strong>References</strong><br>

docs/assets/control.png

@@ -79,8 +79,8 @@ <h3 class="d-inline-block mr-2">
  <code>gram (<var>sys</var>, &quot;o&quot;)</code> returns the observability gramian of the
  (continuous- or discrete-time) system <var>sys</var>.
  <code>gram (<var>a</var>, <var>b</var>)</code> returns the controllability gramian
- <var>Wc</var> of the continuous-time system <em>dx/dt = a x + b u</em>;
- i.e., <var>Wc</var> satisfies <em>a Wc + m Wc&rsquo; + b b&rsquo; = 0</em>.
+ <var>Wc</var> of the continuous-time system <math>d&times;/dt = a&times; + b u</math>;
+ i.e., <var>Wc</var> satisfies <math>a Wc + m Wc&rsquo; + b b&rsquo; = 0</math>.
 </p>
 <div class="ms-5">