chore: update category slugs

Author: hashemix

Cargo.toml

@@ -2,7 +2,7 @@
 name = "rust-mcp-schema"
 version = "0.1.0"
 authors = ["Ali Hashemi"]
-categories = ["Model Context Protocol", "MCP Protocol", "MCP SDK"]
+categories = ["data-structures", "parser-implementations", "parsing"]
 description = "Type-safe implementation of the Model Context Protocol in Rust, designed to reduce errors and accelerate development with powerful utilities."
 repository = "https://github.com/rust-mcp-stack/rust-mcp-schema"
 documentation = "https://docs.rs/rust-mcp-schema"