Add note about semgrep being inconsistent with minified javascript

doc/user/application_security/sast/index.md

@@ -518,6 +518,7 @@ Experimental features available are:
 
 - Enable scanning of iOS and Android apps using the [MobSF analyzer](https://gitlab.com/gitlab-org/security-products/analyzers/mobsf/).
 - Enable the [semgrep analyzer](https://gitlab.com/gitlab-org/security-products/analyzers/semgrep/).
+  - Semgrep may be inconsistent when reporting vulnerabilities found in minified JavaScript files.
 
 #### Enable experimental features