Update x.py

Refactor string formatting by replacing str.format() with f-strings for improved readability and efficiency.

Author: x0root

x.py

@@ -31,18 +31,16 @@
 
     # soft deprecation of old python versions
     skip_check = os.environ.get("RUST_IGNORE_OLD_PYTHON") == "1"
-    if not skip_check and (major < 3 or (major == 3 and minor < 6)):
-        msg = cleandoc(
-            """
-            Using python {}.{} but >= 3.6 is recommended. Your python version
-            should continue to work for the near future, but this will
-            eventually change. If python >= 3.6 is not available on your system,
-            please file an issue to help us understand timelines.
-
-            This message can be suppressed by setting `RUST_IGNORE_OLD_PYTHON=1`
-        """.format(major, minor)
-        )
-        warnings.warn(msg, stacklevel=1)
+if not skip_check and (major < 3 or (major == 3 and minor < 6)):
+    msg = cleandoc(f"""
+        Using python {major}.{minor} but >= 3.6 is recommended. Your python version
+        should continue to work for the near future, but this will
+        eventually change. If python >= 3.6 is not available on your system,
+        please file an issue to help us understand timelines.
+
+        This message can be suppressed by setting `RUST_IGNORE_OLD_PYTHON=1`
+    """)
+    warnings.warn(msg, stacklevel=1)
 
     rust_dir = os.path.dirname(os.path.abspath(__file__))
     # For the import below, have Python search in src/bootstrap first.