refactor: refactor tool macros and router implementation (#261)

* refactor: refactor tool macros and router implementation

- Updated the `#[tool(tool_box)]` macro to `#[tool_router]` across various modules for consistency.
- Enhanced the `Calculator`, `Counter`, and `GenericService` structs to utilize `ToolRouter` for handling tool calls.
- Introduced `Parameters` struct for better parameter handling in tool functions.
- Added new methods for listing tools and calling tools in server handlers.
- Improved test cases to reflect changes in tool routing and parameter handling.
- Updated documentation and examples to align with the new router structure.

* fix: fix fmt and build error

* fix: fix test failure

* docs: documents for macros, fix ci

* fix: fix ci

* fix: fix wrongly replaced documents

* fix: remove useless file

* fix: change the parameter format for tool_router

* fix: update extract_doc_line to handle existing documentation and clean up unused code in server handler

* doc: update document for macro and examples

* doc: update readme and add contribute guide

* fix: fix type

crates/rmcp/tests/test_tool_routers.rs

@@ -0,0 +1,74 @@
+use std::collections::HashMap;
+
+use futures::future::BoxFuture;
+use rmcp::{
+    ServerHandler,
+    handler::server::{
+        router::tool::ToolRouter,
+        tool::{CallToolHandler, Parameters},
+    },
+};
+
+#[derive(Debug, Default)]
+pub struct TestHandler<T: 'static = ()> {
+    pub _marker: std::marker::PhantomData<fn(*const T)>,
+}
+
+impl<T: 'static> ServerHandler for TestHandler<T> {}
+#[derive(Debug, schemars::JsonSchema, serde::Deserialize, serde::Serialize)]
+pub struct Request {
+    pub fields: HashMap<String, String>,
+}
+
+#[derive(Debug, schemars::JsonSchema, serde::Deserialize, serde::Serialize)]
+pub struct Sum {
+    pub a: i32,
+    pub b: i32,
+}
+
+#[rmcp::tool_router(router = test_router_1)]
+impl<T> TestHandler<T> {
+    #[rmcp::tool]
+    async fn async_method(&self, Parameters(Request { fields }): Parameters<Request>) {
+        drop(fields)
+    }
+}
+
+#[rmcp::tool_router(router = test_router_2)]
+impl<T> TestHandler<T> {
+    #[rmcp::tool]
+    fn sync_method(&self, Parameters(Request { fields }): Parameters<Request>) {
+        drop(fields)
+    }
+}
+
+#[rmcp::tool]
+async fn async_function<T>(
+    _callee: &TestHandler<T>,
+    Parameters(Request { fields }): Parameters<Request>,
+) {
+    drop(fields)
+}
+
+#[rmcp::tool]
+fn async_function2<T>(_callee: &TestHandler<T>) -> BoxFuture<'_, ()> {
+    Box::pin(async move {})
+}
+
+#[test]
+fn test_tool_router() {
+    let test_tool_router: ToolRouter<TestHandler<()>> = ToolRouter::<TestHandler<()>>::new()
+        .with_route((async_function_tool_attr(), async_function))
+        .with_route((async_function2_tool_attr(), async_function2))
+        + TestHandler::<()>::test_router_1()
+        + TestHandler::<()>::test_router_2();
+    let tools = test_tool_router.list_all();
+    assert_eq!(tools.len(), 4);
+    assert_handler(TestHandler::<()>::async_method);
+}
+
+fn assert_handler<S, H, A>(_handler: H)
+where
+    H: CallToolHandler<S, A>,
+{
+}