larify pip3 install options.

In some cases --upgrade or --force-reinstall is needed when installing
a python module.  Add some notes describing these options.

If one of the above options is used, --no-deps may be needed to avoid
reinstalling package dependencies.  Note this option also.

general/prog/mako.xml

@@ -80,25 +80,24 @@
 
     <sect3 role="installation">
       <title>Installation of Mako</title>
-<!--
+
       <para>
         Build the module:
       </para>
 
 <screen><userinput>pip3 wheel -w dist - -no-build-isolation - -no-deps $PWD</userinput></screen>
--->
+
       <para>
         Install the module as the &root; user:
       </para>
-<!--
+
 <screen role="root"><userinput>pip3 install - -no-index - -find-links dist - -no-cache-dir Mako</userinput></screen>
--->
-<screen role="root"><userinput>python3 setup.py install --optimize=1</userinput></screen>
+
     </sect3>
-<!--
+
     <xi:include xmlns:xi="http://www.w3.org/2001/XInclude"
       href="../../xincludes/pip3-cmd-explain.xml"/>
--->
+
     <sect3 role="content">
       <title>Contents</title>
 

xincludes/pip3-cmd-explain.xml

@@ -41,5 +41,24 @@
       a warning when installing as the &root; user.
     </para>
 
+    <para>
+      <option>--upgrade</option>: Upgrade the package to the newest
+       available version.  This option is used with the install command
+       if a version of the package is already installed.
+    </para>
+
+    <para>
+      <option>--force-reinstall</option>: Reinstall the package even if
+      it is up-to-date. This option is used with the install command
+      if reinstalling the package or reverting to an earlier version
+      of the package.
+    </para>
+
+    <para>
+      <option>--no-deps</option>: Do not install package dependencies.
+      This option may be needed with the --upgrade or --force-reinstall
+      options.
+    </para>
+
   </sect3>