JS: Add change note

Author: asger-semmle

change-notes/1.21/analysis-javascript.md

@@ -42,6 +42,7 @@
 | Useless assignment to property | Fewer false-positive results | This rule now ignore reads of additional getters. |
 | Unreachable statement | Unreachable throws no longer give an alert | This ignores unreachable throws, as they could be intentional (for example, to placate the TS compiler). |
 | Incorrect suffix check | Fewer false-positive results | This rule now recognizes valid checks in more cases. |
+| Tainted path | More results and fewer false-positive results | This rule now analyses path manipulation code more precisely. |
 
 ## Changes to QL libraries