Update books

ehuss · ehuss · commit ec10c4f7f2fb · 2022-01-03T19:45:10.000-08:00
diff --git a/src/doc/book b/src/doc/book
@@ -1 +1 @@
-Subproject commit 8a0bb3c96e71927b80fa2286d7a5a5f2547c6aa4
+Subproject commit d3740fb7aad0ea4a80ae20f64dee3a8cfc0c5c3c
diff --git a/src/doc/reference b/src/doc/reference
@@ -1 +1 @@
-Subproject commit 06f9e61931bcf58b91dfe6c924057e42ce273ee1
+Subproject commit f8ba2f12df60ee19b96de24ae5b73af3de8a446b
diff --git a/src/doc/rustc-dev-guide b/src/doc/rustc-dev-guide
@@ -1 +1 @@
-Subproject commit 9bf0028b557798ddd07a6f652e4d0c635d3d6620
+Subproject commit 875464457c4104686faf667f47848aa7b0f0a744
