redirect rust-next pages to rust-2021 index

Author: nikomatsakis

book.toml

@@ -78,3 +78,19 @@ git-repository-url = "https://github.com/rust-lang/edition-guide"
 "/rust-2018/platform-and-target-support/msvc-toolchain-support.html" = "/rust-2018/index.html"
 "/rust-2018/platform-and-target-support/musl-support-for-fully-static-binaries.html" = "/rust-2018/index.html"
 "/rust-2018/platform-and-target-support/cdylib-crates-for-c-interoperability.html" = "/rust-2018/index.html"
+"/rust-next/index.html" = "/rust-2021/index.html"
+"/rust-next/edition-changes.html" = "/rust-2021/index.html"
+"/rust-next/dbg-macro.html" = "/rust-2021/index.html"
+"/rust-next/no-jemalloc.html" = "/rust-2021/index.html"
+"/rust-next/uniform-paths.html" = "/rust-2021/index.html"
+"/rust-next/literal-macro-matcher.html" = "/rust-2021/index.html"
+"/rust-next/qustion-mark-operator-in-macros.html" = "/rust-2021/index.html"
+"/rust-next/const-fn.html" = "/rust-2021/index.html"
+"/rust-next/pin.html" = "/rust-2021/index.html"
+"/rust-next/no-more-fnbox.html" = "/rust-2021/index.html"
+"/rust-next/alternative-cargo-registries.html" = "/rust-2021/index.html"
+"/rust-next/tryfrom-and-tryinto.html" = "/rust-2021/index.html"
+"/rust-next/future.html" = "/rust-2021/index.html"
+"/rust-next/alloc.html" = "/rust-2021/index.html"
+"/rust-next/maybe-uninit.html" = "/rust-2021/index.html"
+"/rust-next/cargo-vendor.html" = "/rust-2021/index.html"