message: fix x-history help desc.
diff: @@ -91,7 +91,7 @@ namespace vcpkg::Help
  " vcpkg list List installed packages\n"
  " vcpkg update Display list of packages for updating\n"
  " vcpkg upgrade Rebuild all outdated packages\n"
  - " vcpkg history <pkg> Shows the history of CONTROL versions of a package\n"
  + " vcpkg x-history <pkg> Shows the history of CONTROL versions of a package\n"
  " vcpkg hash <file> [alg] Hash a file by specific algorithm, default SHA512\n"
  " vcpkg help topics Display the list of help topics\n"
  " vcpkg help <topic> Display help for a specific topic\n"
  