Function python_tool_install_hint 

pub fn python_tool_install_hint(tool: &str) -> String

Generate an install hint for a standalone Python CLI tool (e.g. bandit, flawfinder, cpplint).

This helper is retained outside the tools::install module because it serves a different abstraction: callers identify the tool by its package name (not a Language/ToolRole pair). Security scanners, fixers, and similar call sites use this when they need a user-facing “install X” message without registering the tool in TOOL_INSTALLS.