fix: python -> python3

Signed-off-by: Henry Schreiner <[email protected]>

Author: henryiii

docs/reference/cli.md

@@ -6,54 +6,54 @@ environment.
 
 ## Build utilities
 
-```{program-output} python -m scikit_build_core.build --help
+```{program-output} python3 -m scikit_build_core.build --help
 
 ```
 
 ### Build requirements
 
-```{program-output} python -m scikit_build_core.build requires --help
+```{program-output} python3 -m scikit_build_core.build requires --help
 
 ```
 
 Example:
 
-```{command-output} python -m scikit_build_core.build requires
+```{command-output} python3 -m scikit_build_core.build requires
 :cwd: ../examples/getting_started/c
 
 ```
 
 ### Project table
 
-```{program-output} python -m scikit_build_core.build project-table --help
+```{program-output} python3 -m scikit_build_core.build project-table --help
 
 ```
 
 Example:
 
-```{command-output} python -m scikit_build_core.build project-table
+```{command-output} python3 -m scikit_build_core.build project-table
 :cwd: ../examples/getting_started/c
 
 ```
 
 ## Wheel tag
 
-```{program-output} python -m scikit_build_core.builder.wheel_tag --help
+```{program-output} python3 -m scikit_build_core.builder.wheel_tag --help
 
 ```
 
 Example:
 
-```{command-output} python -m scikit_build_core.builder.wheel_tag
+```{command-output} python3 -m scikit_build_core.builder.wheel_tag
 
 ```
 
 ## File API tools
 
-```{program-output} python -m scikit_build_core.file_api.query --help
+```{program-output} python3 -m scikit_build_core.file_api.query --help
 
 ```
 
-```{program-output} python -m scikit_build_core.file_api.reply --help
+```{program-output} python3 -m scikit_build_core.file_api.reply --help
 
 ```