Update all lint diagnostics to store their span

Author: fmease

Diff for: compiler/rustc_borrowck/src/lib.rs

@@ -409,7 +409,7 @@ fn do_mir_borrowck<'tcx>(
 
         let mut_span = tcx.sess.source_map().span_until_non_whitespace(span);
 
-        tcx.emit_node_span_lint(UNUSED_MUT, lint_root, span, VarNeedNotMut { span: mut_span })
+        tcx.emit_node_lint(UNUSED_MUT, lint_root, VarNeedNotMut { span, mut_span })
     }
 
     let tainted_by_errors = mbcx.emit_errors();

Diff for: compiler/rustc_borrowck/src/session_diagnostics.rs

@@ -49,8 +49,10 @@ pub(crate) struct GenericDoesNotLiveLongEnough {
 #[derive(LintDiagnostic)]
 #[diag(borrowck_var_does_not_need_mut)]
 pub(crate) struct VarNeedNotMut {
-    #[suggestion(style = "short", applicability = "machine-applicable", code = "")]
+    #[primary_span]
     pub span: Span,
+    #[suggestion(style = "short", applicability = "machine-applicable", code = "")]
+    pub mut_span: Span,
 }
 #[derive(Diagnostic)]
 #[diag(borrowck_var_cannot_escape_closure)]