[4.3] Inclusive Naming master (various)

We should be using inclusive naming throughout the cms not just in the language strings.

Changes "master" to "main" or "source" as appropriate,

### Rationale
https://inclusivenaming.org/word-lists/tier-1/_master/

### Test
Code review Only

### Documentation
New page will be added to manual.joomla.org shortly

### Note
This is part of a series of pull requests that are submitted separately to make reviewing easier

administrator/components/com_users/src/Model/UsersModel.php

@@ -235,7 +235,7 @@ public function getItems()
                 return false;
             }
 
-            // Second pass: collect the group counts into the master items array.
+            // Second pass: collect the group counts into the main items array.
             foreach ($items as &$item) {
                 if (isset($userGroups[$item->id])) {
                     $item->group_count = $userGroups[$item->id]->group_count;

build/media_source/templates/site/cassiopeia/scss/tools/variables/_variables.scss

@@ -204,7 +204,7 @@ $form-select-multiple-padding-y:    .3rem !default;
 
 $form-range-thumb-active-bg:        tint-color($standard-color-primary, 70%) !default;
 
-// Z-index master list
+// Z-index source list
 $zindex-negative:                     -1 !default;
 $zindex-actions:                      auto !default;
 $zindex-toolbar:                      1000 !default;

components/com_content/src/Model/ArchiveModel.php

@@ -82,7 +82,7 @@ protected function populateState($ordering = null, $direction = null)
     }
 
     /**
-     * Get the master query for retrieving a list of articles subject to the model state.
+     * Get the main query for retrieving a list of articles subject to the model state.
      *
      * @return  \Joomla\Database\DatabaseQuery
      *

plugins/extension/joomla/src/Extension/Joomla.php

@@ -21,7 +21,7 @@
 // phpcs:enable PSR1.Files.SideEffects
 
 /**
- * Joomla! master extension plugin.
+ * Joomla! main extension plugin.
  *
  * @since  1.6
  */