docs: add -p parameter to the cargo run commands in documentation

[dj707chen]

Add -p parameter to the cargo run commands in README.md files and other documentation to fix error.

Motivation and Context

When I launched the following command as documented in examples/servers/README.md at the examples/server directory:

cargo run --example servers_counter_stdio

It ran well, but when I launched it at repository root or places other than the examples/server subtree, I got error:

error: no example target named `servers_counter_stdio` in default-run packages

Add the -p parameter to make it runs at all places:

cargo run -p mcp-server-examples --example servers_counter_stdio

How Has This Been Tested?

Run the new commands.

Breaking Changes

(None)

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation update

Checklist

• I have read the MCP Documentation
• My code follows the repository's style guidelines
• New and existing tests pass locally
• I have added appropriate error handling
• I have added or updated documentation as needed

Additional context

(None)