include x and x.ps1 scripts in tarball sources

Helps to provide 1:1 build experience between git-managed and tarball sources.

Signed-off-by: onur-ozkan <work@onurozkan.dev>

src/bootstrap/src/core/build_steps/dist.rs

@@ -1008,6 +1008,8 @@ impl Step for PlainSourceTarball {
             "README.md",
             "RELEASES.md",
             "REUSE.toml",
+            "x",
+            "x.ps1",
             "x.py",
             // tidy-alphabetical-end
         ];