Add section on creating an info_player_start

doc/manual.adoc

@@ -622,3 +622,18 @@ the applied textures are also shown in table at the lower left.
 When you have chosen the desired model, click *OK* to insert it into the map.
 The model will be inserted at the position where you originally right-clicked to
 show the model chooser.
+
+==== Creating a player start marker
+
+The game requires a special entity (`info_player_start`) to mark the position at
+which the player should enter the map. Without such an entity the map will be
+unplayable.
+
+To create this entity, ensure that nothing is selected then *Right click* in the
+2D view and choose *Create player start here*. DarkRadiant will create the
+player start entity at the clicked position.
+
+Since it makes no sense to have more than one player start location, DarkRadiant
+will not enable the *Create player start here* menu option if there is already
+an `info_player_start` in the map. Instead, you may choose *Move player start
+here* to move the existing entity to the clicked position.

doc/manual.html

@@ -461,6 +461,7 @@ <h1>DarkRadiant User Guide</h1>
 <ul class="sectlevel3">
 <li><a href="#_creating_lights">Creating lights</a></li>
 <li><a href="#_creating_models">Creating models</a></li>
+<li><a href="#_creating_a_player_start_marker">Creating a player start marker</a></li>
 </ul>
 </li>
 </ul>
@@ -1460,13 +1461,32 @@ <h4 id="_creating_models">Creating models</h4>
 show the model chooser.</p>
 </div>
 </div>
+<div class="sect3">
+<h4 id="_creating_a_player_start_marker">Creating a player start marker</h4>
+<div class="paragraph">
+<p>The game requires a special entity (<code>info_player_start</code>) to mark the position at
+which the player should enter the map. Without such an entity the map will be
+unplayable.</p>
+</div>
+<div class="paragraph">
+<p>To create this entity, ensure that nothing is selected then <strong>Right click</strong> in the
+2D view and choose <strong>Create player start here</strong>. DarkRadiant will create the
+player start entity at the clicked position.</p>
+</div>
+<div class="paragraph">
+<p>Since it makes no sense to have more than one player start location, DarkRadiant
+will not enable the <strong>Create player start here</strong> menu option if there is already
+an <code>info_player_start</code> in the map. Instead, you may choose <strong>Move player start
+here</strong> to move the existing entity to the clicked position.</p>
+</div>
+</div>
 </div>
 </div>
 </div>
 </div>
 <div id="footer">
 <div id="footer-text">
-Last updated 2018-08-15 21:04:29 BST
+Last updated 2018-08-15 21:11:53 BST
 </div>
 </div>
 </body>