style: align math/strided/special/smsktrunc with namespace conventions

Inserted `stdmath`, `mathematics`, `math` keywords after `stdlib` to match
the keyword ordering present in 69/81 (85%) of namespace siblings.

Author: claude

lib/node_modules/@stdlib/math/strided/special/smsktrunc/package.json

@@ -54,6 +54,9 @@
   ],
   "keywords": [
     "stdlib",
+    "stdmath",
+    "mathematics",
+    "math",
     "math.trunc",
     "trunc",
     "truncate",