Improve docs regarding RTL migration (#32771)

* docs(migrations): add a note regarding migration from v4 used for RTL layouts

* docs(RTL): LTR & RTL at the same time

* docs(utilities): how-to use the API to rename utilities

* docs(RTL): mention issue when nesting styles with .ltr / .rtl

site/content/docs/5.0/utilities/api.md

@@ -289,6 +289,25 @@ $utilities: map-merge(
 );
 ```
 
+#### Rename utilities
+
+Missing v4 utilities, or used to another naming convention? The utilities API can be used to override the resulting `class` of a given utility—for example, to rename `.ms-*` utilities to oldish `.ml-*`:
+
+```scss
+@import "bootstrap/scss/functions";
+@import "bootstrap/scss/variables";
+@import "bootstrap/scss/utilities";
+
+$utilities: map-merge(
+  $utilities, (
+    "margin-start": map-merge(
+      map-get($utilities, "margin-start"),
+      ( class: ml ),
+    ),
+  )
+);
+```
+
 ### Remove utilities
 
 Remove any of the default utilities by setting the group key to `null`. For example, to remove all our `width` utilities, create a `$utilities` `map-merge` and add `"width": null` within.