Documentation: Add documentation for more objects per GRF

docs/newgrf-additions-nml.html

@@ -39,6 +39,7 @@
 	<li><a href="#railtype-variables">Railtype variables</a></li>
 	<li><a href="#roadtype-properties">Roadtype properties</a></li>
 	<li><a href="#tramtype-properties">Tramtype properties</a></li>
+	<li><a href="#object-ids">Object IDs</a></li>
 	<li><a href="#object-properties">Object properties</a></li>
 	<li><a href="#object-variables">Object variables</a></li>
 	<li><a href="#global-variable-properties">Global variables properties</a></li>
@@ -192,6 +193,12 @@
 		</td>
 	</tr>
 	</table>
+	<h3 id="object-ids"><a href="https://newgrf-specs.tt-wiki.net/wiki/NML:Objects#Object_IDs">Object IDs</a></h3>
+	<p>
+		Object IDs are NewGRF-local and can be freely chosen in the 0..63999 range, as of the <span class="code">more_objects_per_grf</span> feature.<br />
+		When loaded into a version of OpenTTD without this feature, IDs are limited to the range: 0..254.
+		Any objects with IDs outside this range will be skipped.
+	</p>
 	<h3 id="object-properties"><a href="https://newgrf-specs.tt-wiki.net/wiki/NML:Objects#Object_properties">Object properties</a></h3>
 	<table>
 	<tr><th>Property</th><th>Value range</th><th>Comment</th></tr>

docs/newgrf-additions.html

@@ -50,6 +50,7 @@
 	<li><a href="#varaction2_railtypes">Variational Action 2 - Railtypes</a></li>
 	<li><a href="#varaction2_object">Variational Action 2 - Objects</a></li>
 	<li><a href="#varaction2_signals">Variational Action 2 - Signals (Feature 0E)</a></li>
+	<li><a href="#a3objects">Action 3 - Objects</a></li>
 	<li><a href="#a3signals">Action 3 - Signals (Feature 0E)</a></li>
 	<li><a href="#action5">Action 14 - Type ID Mapping for Action 5</a></li>
 	<li><a href="#feature-id-mapping">Action 14 - Feature ID Mapping</a></li>
@@ -767,6 +768,11 @@
 	<p>This is indicated by the feature name: <font face="monospace">action0_signals_style</font>, version 1</p>
 	<br />
 	<br />
+	<h3 id="a3objects"><a href="https://newgrf-specs.tt-wiki.net/wiki/Action3">Action 3 - Objects</a></h3>
+	<p>If feature name <font face="monospace">more_objects_per_grf</font> is present, the Action 3 ID field is an extended byte, and GRFs may define more than 255 object types.<br />
+	Otherwise, only 255 object types may be defined per GRF, and the extended byte format may not be used.</p>
+	<br />
+	<br />
 	<h3 id="a3signals"><a href="https://newgrf-specs.tt-wiki.net/wiki/Action3">Action 3 - Signals (Feature 0E)</a></h3>
 	<p>Note that Action 3 feature 0E is not supported (does nothing) in standard OpenTTD.</p>
 	<p>This implementation of feature 0E is not the same as that in TTDPatch.</p>