Improve formatting of config option documentation

docs/configuration/options.md

@@ -13,13 +13,35 @@ Tells isort to set the known standard library based on the specified Python vers
 
 **Type:** String  
 **Default:** `py3`  
-**Config default:** `py3`  
+**Config default:** `3`  
 **Python & Config File Name:** py_version  
 **CLI Flags:**
 
 - --py
 - --python-version
 
+**Examples:**
+
+### Example `.isort.cfg`
+
+```
+[settings]
+py_version=39
+
+```
+
+### Example `pyproject.toml`
+
+```
+[tool.isort]
+py_version=39
+
+```
+
+### Example cli usage
+
+`isort --py 39`
+
 ## Force To Top
 
 Force specific imports to the top of their appropriate section.

scripts/build_config_option_docs.py

@@ -291,6 +291,13 @@ def __str__(self):
     ),
     "multi_line_output": Example(cfg="multi_line_output=3", pyproject_toml="multi_line_output = 3"),
     "show_version": Example(cli="isort --version"),
+    "py_version": Example(cli="isort --py 39",
+    pyproject_toml="""
+py_version=39
+""",
+    cfg="""
+py_version=39
+""")
 }
 
 
@@ -335,6 +342,8 @@ def config_default(default: Any) -> str:
     if default_str in CONFIG_DEFAULTS:
         return CONFIG_DEFAULTS[default_str]
 
+    if default_str.startswith("py"):
+        return default_str[2:]
     return default_str