Remove unnecessary uv runin README (#5792)

* Update README.md

Remove unnecessary `uv run`

* uv comment

---------

Co-authored-by: Jeong YunWon <jeong@youknowone.org>

README.md

@@ -226,7 +226,7 @@ To enhance CPython compatibility, try to increase unittest coverage by checking
 Another approach is to checkout the source code: builtin functions and object
 methods are often the simplest and easiest way to contribute.
 
-You can also simply run `uv run python -I whats_left.py` to assist in finding any unimplemented
+You can also simply run `python -I whats_left.py` to assist in finding any unimplemented
 method.
 
 ## Compiling to WebAssembly

whats_left.py

@@ -40,7 +40,7 @@ if implementation != "CPython":
     sys.exit(f"whats_left.py must be run under CPython, got {implementation} instead")
 if sys.version_info[:2] < (3, 13):
     sys.exit(
-        f"whats_left.py must be run under CPython 3.13 or newer, got {implementation} {sys.version} instead"
+        f"whats_left.py must be run under CPython 3.13 or newer, got {implementation} {sys.version} instead. If you have uv, try `uv run python -I whats_left.py` to select a proper Python interpreter easier."
     )