multiple_inherent_impl: make lint adhere to lint message convention

Author: matthiaskrgr

clippy_lints/src/inherent_impl.rs

@@ -81,9 +81,9 @@ impl<'tcx> LateLintPass<'tcx> for MultipleInherentImpl {
                             cx,
                             MULTIPLE_INHERENT_IMPL,
                             *additional_span,
-                            "Multiple implementations of this structure",
+                            "multiple implementations of this structure",
                             |diag| {
-                                diag.span_note(*initial_span, "First implementation here");
+                                diag.span_note(*initial_span, "first implementation here");
                             },
                         )
                     })

tests/ui/impl.stderr

@@ -1,4 +1,4 @@
-error: Multiple implementations of this structure
+error: multiple implementations of this structure
   --> $DIR/impl.rs:10:1
    |
 LL | / impl MyStruct {
@@ -7,23 +7,23 @@ LL | | }
    | |_^
    |
    = note: `-D clippy::multiple-inherent-impl` implied by `-D warnings`
-note: First implementation here
+note: first implementation here
   --> $DIR/impl.rs:6:1
    |
 LL | / impl MyStruct {
 LL | |     fn first() {}
 LL | | }
    | |_^
 
-error: Multiple implementations of this structure
+error: multiple implementations of this structure
   --> $DIR/impl.rs:24:5
    |
 LL | /     impl super::MyStruct {
 LL | |         fn third() {}
 LL | |     }
    | |_____^
    |
-note: First implementation here
+note: first implementation here
   --> $DIR/impl.rs:6:1
    |
 LL | / impl MyStruct {