session: diagnostic migration lint on more fns

Apply the diagnostic migration lint to more functions on `Session`.

Signed-off-by: David Wood <david.wood@huawei.com>

compiler/rustc_session/src/errors.rs

@@ -375,3 +375,9 @@ pub fn report_lit_error(sess: &ParseSess, err: LitError, lit: token::Lit, span:
         }
     }
 }
+
+#[derive(Diagnostic)]
+#[diag(session_optimization_fuel_exhausted)]
+pub struct OptimisationFuelExhausted {
+    pub msg: String,
+}