Improve documentation and modernize type hints

src/rp/render.py

@@ -14,18 +14,37 @@ from rp.pager import MousePager
 
 @dataclass
 class RenderOptions:
+    """Rendering options for file display.
+
+    Attributes:
+        theme: Pygments color theme name.
+        line_numbers: Show line numbers. ``None`` enables them for code only.
+        pager: Use pager for output. ``None`` auto-detects terminal output.
+    """
+
     theme: str = "monokai"
     line_numbers: bool | None = None
     pager: bool | None = None
 
 
-_MARKDOWN_TYPES = {"markdown", "md"}
-_JSON_TYPES = {"json"}
+_MARKDOWN_TYPES: set[str] = {"markdown", "md"}
+_JSON_TYPES: set[str] = {"json"}
 
 
 def render(
     content: str, file_type: str, console: Console, options: RenderOptions
 ) -> None:
+    """Render content to the console with syntax highlighting.
+
+    Renders Markdown with Rich Markdown, JSON with Rich JSON with a Syntax
+    fallback, and all other types with Pygments Syntax highlighting.
+
+    Args:
+        content: File content to render.
+        file_type: Pygments lexer name.
+        console: Rich console to render to.
+        options: Rendering options (theme, line numbers, pager).
+    """
     line_numbers = options.line_numbers
     if line_numbers is None:
         line_numbers = file_type not in _MARKDOWN_TYPES and file_type not in _JSON_TYPES