Make proc_macro span's line & column 1-indexed, as documented

That is, make the fake number that we return 1 and not 0.

crates/proc-macro-srv/src/server_impl/token_id.rs

@@ -291,11 +291,11 @@ impl server::Span for TokenIdServer {
     }
 
     fn line(&mut self, _span: Self::Span) -> usize {
-        0
+        1
     }
 
     fn column(&mut self, _span: Self::Span) -> usize {
-        0
+        1
     }
 }