Missing documentation for inspector_port parameter in Local development settings

## Issue

The page https://developers.cloudflare.com/workers/wrangler/configuration/#local-development-settings is missing documentation for the `inspector_port` parameter in the "Local development settings" section.

## Details

The `inspector_port` parameter is defined in the Wrangler codebase:
https://github.com/cloudflare/workers-sdk/blob/4eb1da9b24247a10a031ecced2cc829243024f84/packages/workers-utils/src/config/config.ts#L198-L269

This parameter is essential when running multiple development servers simultaneously, as it allows configuring the port used for the inspector protocol to avoid port conflicts.

## Suggested Fix

Add documentation for the `inspector_port` parameter to the "Local development settings" section, explaining:
- What the parameter does
- Why it's needed (avoiding port conflicts when running multiple dev servers)
- Default value
- Example usage in `wrangler.toml`