style: align stats/base/dists/uniform/mgf with namespace conventions

Added missing `probability` keyword in package.json keywords array (present in 93% of sibling packages in `stats/base/dists/uniform`).

Author: claude

lib/node_modules/@stdlib/stats/base/dists/uniform/mgf/package.json

@@ -58,6 +58,7 @@
     "stats",
     "distribution",
     "dist",
+    "probability",
     "mgf",
     "generating functions",
     "moments",