Auto merge of rust-lang#6530 - m-ou-se:2021, r=phansch

Initial support for Rust 2021.

Clippy treated Rust 2021 as Rust 2015, because 2018 was checked with `==` instead of `>=`. This fixes that, such that 2018-specific things are also enabled for 2021.

changelog: Added support for Rust 2021.

Author: bors

clippy_lints/src/macro_use.rs

@@ -105,7 +105,7 @@ impl MacroUseImports {
 impl<'tcx> LateLintPass<'tcx> for MacroUseImports {
     fn check_item(&mut self, cx: &LateContext<'_>, item: &hir::Item<'_>) {
         if_chain! {
-            if cx.sess().opts.edition == Edition::Edition2018;
+            if cx.sess().opts.edition >= Edition::Edition2018;
             if let hir::ItemKind::Use(path, _kind) = &item.kind;
             if let Some(mac_attr) = item
                 .attrs

clippy_lints/src/single_component_path_imports.rs

@@ -40,7 +40,7 @@ impl EarlyLintPass for SingleComponentPathImports {
     fn check_item(&mut self, cx: &EarlyContext<'_>, item: &Item) {
         if_chain! {
             if !in_macro(item.span);
-            if cx.sess.opts.edition == Edition::Edition2018;
+            if cx.sess.opts.edition >= Edition::Edition2018;
             if !item.vis.kind.is_pub();
             if let ItemKind::Use(use_tree) = &item.kind;
             if let segments = &use_tree.prefix.segments;