change (config): stderr msgs

primitives/api/test/tests/ui/declaring_old_block.stderr

@@ -10,10 +10,10 @@ error: `Block: BlockT` generic parameter will be added automatically by the `dec
 4 |     pub trait Api<Block: BlockT> {
   |                   ^^^^^
 
-warning: unused import: `sp_runtime::traits::Block as BlockT`
+error: unused import: `sp_runtime::traits::Block as BlockT`
  --> $DIR/declaring_old_block.rs:1:5
   |
 1 | use sp_runtime::traits::Block as BlockT;
   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
-  = note: `#[warn(unused_imports)]` on by default
+  = note: `-D unused-imports` implied by `-D warnings`

primitives/api/test/tests/ui/declaring_own_block_with_different_name.stderr

@@ -4,10 +4,10 @@ error: `Block: BlockT` generic parameter will be added automatically by the `dec
 4 |     pub trait Api<B: BlockT> {
   |                      ^^^^^^
 
-warning: unused import: `sp_runtime::traits::Block as BlockT`
+error: unused import: `sp_runtime::traits::Block as BlockT`
  --> $DIR/declaring_own_block_with_different_name.rs:1:5
   |
 1 | use sp_runtime::traits::Block as BlockT;
   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
-  = note: `#[warn(unused_imports)]` on by default
+  = note: `-D unused-imports` implied by `-D warnings`

primitives/api/test/tests/ui/impl_two_traits_with_same_name.stderr

@@ -4,10 +4,10 @@ error: Two traits with the same name detected! The trait name is used to generat
 32 |     impl second::Api<Block> for Runtime {
    |                  ^^^
 
-warning: unused import: `super::*`
+error: unused import: `super::*`
   --> $DIR/impl_two_traits_with_same_name.rs:18:6
    |
 18 |     use super::*;
    |         ^^^^^^^^
    |
-   = note: `#[warn(unused_imports)]` on by default
+   = note: `-D unused-imports` implied by `-D warnings`

primitives/api/test/tests/ui/mock_only_one_block_type.stderr

@@ -10,10 +10,10 @@ error: First block type found here
 18 |     impl Api<Block> for MockApi {
    |              ^^^^^
 
-warning: unused import: `substrate_test_runtime_client::runtime::Block`
+error: unused import: `substrate_test_runtime_client::runtime::Block`
  --> $DIR/mock_only_one_block_type.rs:1:5
   |
 1 | use substrate_test_runtime_client::runtime::Block;
   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
-  = note: `#[warn(unused_imports)]` on by default
+  = note: `-D unused-imports` implied by `-D warnings`

primitives/api/test/tests/ui/mock_only_one_self_type.stderr

@@ -10,10 +10,10 @@ error: First self type found here
 17 |     impl Api<Block> for MockApi {
    |                         ^^^^^^^
 
-warning: unused import: `substrate_test_runtime_client::runtime::Block`
+error: unused import: `substrate_test_runtime_client::runtime::Block`
  --> $DIR/mock_only_one_self_type.rs:1:5
   |
 1 | use substrate_test_runtime_client::runtime::Block;
   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
-  = note: `#[warn(unused_imports)]` on by default
+  = note: `-D unused-imports` implied by `-D warnings`