Remove reference to Diffence

Diffence was removed with this MR https://gitlab.com/gitlab-org/security-products/analyzers/secrets/merge_requests/16

doc/user/application_security/sast/analyzers.md

@@ -21,7 +21,7 @@ SAST supports the following official analyzers:
 - [`nodejs-scan`](https://gitlab.com/gitlab-org/security-products/analyzers/nodejs-scan) (NodeJsScan)
 - [`phpcs-security-audit`](https://gitlab.com/gitlab-org/security-products/analyzers/phpcs-security-audit) (PHP CS security-audit)
 - [`pmd-apex`](https://gitlab.com/gitlab-org/security-products/analyzers/pmd-apex) (PMD (Apex only))
-- [`secrets`](https://gitlab.com/gitlab-org/security-products/analyzers/secrets) (Secrets (Gitleaks, TruffleHog & Diffence secret detectors))
+- [`secrets`](https://gitlab.com/gitlab-org/security-products/analyzers/secrets) (Secrets (Gitleaks & TruffleHog secret detectors))
 - [`security-code-scan`](https://gitlab.com/gitlab-org/security-products/analyzers/security-code-scan) (Security Code Scan (.NET))
 - [`sobelow`](https://gitlab.com/gitlab-org/security-products/analyzers/sobelow) (Sobelow (Elixir Phoenix))
 - [`spotbugs`](https://gitlab.com/gitlab-org/security-products/analyzers/spotbugs) (SpotBugs with the Find Sec Bugs plugin (Ant, Gradle and wrapper, Grails, Maven and wrapper, SBT))