docs: fix markdown heading in Rust doc comment

Author: Avicennasis

gvm-auth-c/src/lib.rs

@@ -2,7 +2,7 @@
 //
 // SPDX-License-Identifier: GPL-3.0-or-later
 
-//! #gvm-auth-c-lib
+//! # gvm-auth-c-lib
 //! The `gvm-auth-c-lib` crate is a wrapper of the GVM authentication library
 //! `gvm-auth-lib` for use in C.