Track exclusion of .cargo/config.toml from tombi linting

[coderabbitai]

Context

The file .cargo/config.toml is currently excluded from tombi TOML linting because the schema store does not yet have an available schema for this file.

This issue tracks the exclusion until a schema becomes available upstream.

Related

• Upstream tracking issue: Publish .cargo/config.toml jsonschema to schemastore.org for editor  rust-lang/cargo#12883
• PR where exclusion was added: feat(rust): Set up the Cargo workspace for Rust components: #268
• Review comment: feat(rust): Set up the Cargo workspace for Rust components: #268 (comment)
• Requested by: @sitaowang1998