micro_http: fix doctest socket conflicts

Doctests in `lib.rs` and `server.rs` were both using the same hardcoded
socket path `/tmp/example.sock`. When running tests in parallel, this
caused conflicts and sporadic failures with `AddrInUse`.

Fix this by using unique socket paths for each doctest.

Assisted-by: Antigravity:Gemini-3.5-Flash
Signed-off-by: Changyuan Lyu <changyuanl@google.com>

src/lib.rs

@@ -83,7 +83,7 @@
 //! ```
 //! use micro_http::{HttpServer, Response, StatusCode};
 //!
-//! let path_to_socket = "/tmp/example.sock";
+//! let path_to_socket = "/tmp/example_lib.sock";
 //! std::fs::remove_file(path_to_socket).unwrap_or_default();
 //!
 //! // Start the server.

src/server.rs

@@ -226,7 +226,7 @@ impl<T: Read + Write + ScmSocket> ClientConnection<T> {
 /// ```
 /// use micro_http::{HttpServer, Response, StatusCode};
 ///
-/// let path_to_socket = "/tmp/example.sock";
+/// let path_to_socket = "/tmp/example_server.sock";
 /// std::fs::remove_file(path_to_socket).unwrap_or_default();
 ///
 /// // Start the server.