Add mutest-rs to tools list (#646)

Author: mhatzl

arewesafetycriticalyet.org/src/components/ToolsList/available-tools.json

@@ -2,7 +2,7 @@
   "metadata": {
     "title": "Rust Tooling for use in Safety Critical Projects",
     "version": "1.2",
-    "date": "2026-03-07",
+    "date": "2026-05-08",
     "tracked-standards": [
       {
         "name": "ISO 26262",
@@ -249,6 +249,13 @@
       "url": "https://github.com/verifast/verifast",
       "description": "VeriFast is a tool for modular formal verification of the absence of undefined behavior in Rust1 programs that use unsafe blocks and the soundness of Rust modules that use unsafe blocks.",
       "license": "MIT"
+    },
+    {
+      "name": "mutest-rs",
+      "type": "testing",
+      "url": "https://mutest.rs/",
+      "description": "Robust, efficient, safe, and parallel mutation testing tools for Rust.",
+      "license": "Apache 2.0 & MIT"
     }
   ]
 }