DOC Document changes to CMSMain and LeftAndMain

Author: GuySartorelli

en/02_Developer_Guides/15_Customising_the_Admin_Interface/04_CMS_Architecture.md

@@ -450,7 +450,7 @@ class MyAdmin extends LeftAndMain
 ```ss
 <%-- MyRecordInfo.ss --%>
 <div data-pjax-fragment="MyRecordInfo">
-    Current Record: $currentPage.Title
+    Current Record: $currentRecord.Title
 </div>
 ```
 

en/02_Developer_Guides/15_Customising_the_Admin_Interface/How_Tos/Customise_CMS_Tree.md

@@ -13,7 +13,7 @@ by the [jstree](https://jstree.com) library. It is configured through
 `client/src/legacy/LeftAndMain.Tree.js` in the `silverstripe/admin` module, as well as some
 HTML5 metadata generated on its container (see the `data-hints` attribute).
 
-The tree is rendered through [LeftAndMain::getSiteTreeFor()](api:SilverStripe\Admin\LeftAndMain::getSiteTreeFor()),
+The tree is rendered through [LeftAndMain::getTreeFor()](api:SilverStripe\Admin\LeftAndMain::getTreeFor()),
 which recursively collects all nodes based on various filtering criteria.
 The node strictly just has to implement the [Hierarchy](api:SilverStripe\ORM\Hierarchy\Hierarchy) extension,
 but in the CMS usually is a [SiteTree](api:SilverStripe\CMS\Model\SiteTree) object.
@@ -36,7 +36,7 @@ code like this:
             <ins class="jstree-checkbox">&nbsp;</ins>
             <ins class="jstree-icon">&nbsp;</ins>
             <span class="text">
-                <span class="jstree-pageicon"></span>
+                <span class="jstree-recordicon"></span>
                 <span class="item" title="Deleted">New Page</span>
                 <span class="badge deletedonlive">Deleted</span>
             </span>
@@ -65,7 +65,7 @@ use Page;
 
 class HomePage extends Page
 {
-    private static $icon_class = 'font-icon-p-home';
+    private static $cms_icon_class = 'font-icon-p-home';
 
     // ...
 }

en/08_Changelogs/6.0.0.md

@@ -629,7 +629,9 @@ As a result of these changes, the following classes have had their class hierarc
 |[`SubsiteXHRController`](api:SilverStripe\Subsites\Controller\SubsiteXHRController)|`LeftAndMain`|`AdminController`|
 |[`CMSExternalLinksController`](api:SilverStripe\ExternalLinks\Controllers\CMSExternalLinksController)|`Controller`|`AdminController`|
 
-The `tree_class` configuration property on `LeftAndMain` and its subclasses has be renamed to [`model_class`](api:SilverStripe\Admin\LeftAndMain->model_class). This is used in methods like [`getRecord()`](api:SilverStripe\Admin\LeftAndMain::getRecord()) to get a record of the correct class.
+The `tree_class` configuration property on `LeftAndMain` and its subclasses has be renamed to [`model_class`](api:SilverStripe\Admin\LeftAndMain->model_class), and a new [`getModelClass()`](api:SilverStripe\Admin\LeftAndMain::getModelClass()) method has been implemented to return it. This is used in methods like [`getRecord()`](api:SilverStripe\Admin\LeftAndMain::getRecord()) to get a record of the correct class.
+
+The `getModelClass()` method is the same method used in `ModelAdmin` to get the class for the currently accessed tab. This parity means you can predictably call `getModelClass()` on any initialised subclass of `LeftAndMain` and get an appropriate base class to work with.
 
 #### Effects of this refactor in other classes