Document Source Text repeat() shorthand

docs/text/sourcetext.md

@@ -6,6 +6,26 @@ These functions are accessible on the [Text.sourceText](text.md#textsourcetext)
 
 ---
 
+## `repeat()` shorthand
+
+When the JavaScript expression engine is active, After Effects interprets a Source Text value as a JavaScript String. In a Source Text expression, `repeat()` can be called without an explicit receiver to repeat the current text value.
+
+For example, if the Source Text value is `"AE"`, each of these expressions returns `"AEAEAE"`:
+
+```js
+repeat(3);
+value.repeat(3);
+text.sourceText.repeat(3);
+```
+
+!!! note
+    `repeat()` is the standard JavaScript [`String.prototype.repeat()`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/repeat) method, not a global After Effects method. The receiver-less form is specific to a Source Text expression and is undefined on numeric properties. To repeat a different string, call the method on that string explicitly, such as `"AE".repeat(3)`.
+
+!!! warning
+    Adobe documents Source Text's JavaScript String behavior, but does not explicitly document receiver-less dispatch for standard JavaScript methods. This shorthand has been verified in After Effects 26.3 and 27.0 Beta; use the explicit `value.repeat(3)` form when clarity or portability is preferred.
+
+---
+
 ## Attributes
 
 ### SourceText.isHorizontalText