Update PR template to include tool renaming section

[tommaso-moro]

Summary

Now that we support tool aliases for safe tool renaming, we need to ensure that aliases are introduced whenever tools are renamed. This PR updates the PR template to add a heads up to the dev opening the PR and thus ensure this process isn't neglected.

Why

If tools are renamed and their aliases are not updated, we risk breaking the server for users that have a hard reference to those tools in their server config

What changed

• the template was updated to add a section on tool renaming

MCP impact

• No tool or API changes
• Tool schema or behavior changed
• New tool added

Prompts tested (tool changes only)

• n/a

Security / limits

• No security or limits impact
• Auth / permissions considered
• Data exposure, filtering, or token/size limits considered

Lint & tests

• Linted locally with ./script/lint
• Tested locally with ./script/test

Docs

• Not needed
• Updated (README / docs / examples)

[Copilot]

Pull request overview

This PR enhances the pull request template by adding a new "Tool renaming" section to ensure developers don't forget to update tool aliases when renaming tools, which would otherwise break the server for users with hard references to old tool names.

• Adds a new "Tool renaming" section with checkboxes for developers to confirm whether they're renaming tools
• Includes a reference to deprecated_tool_aliases.go where aliases should be added
• Provides a link to documentation for detailed guidance on the tool renaming process