Update various book modules

steveklabnik · steveklabnik · commit 434e601446cf · 2017-03-27T17:41:58.000-04:00
This includes an important fix for rustc contributors in rust-lang/book#571 I'm going to update the other ones as well here while we're at it; no need to spam PRs.
diff --git a/src/doc/book b/src/doc/book
@@ -1 +1 @@
-Subproject commit 9bd223ca406b1170a24942d6474f9e8a56f4a420
+Subproject commit a2c56870d4dc589237102cc5e0fe7b9ebd0d14a1
diff --git a/src/doc/nomicon b/src/doc/nomicon
@@ -1 +1 @@
-Subproject commit d08fe97d12b41c1ed8cc7701e545864132783941
+Subproject commit 616b98444ff4eb5260deee95ee3e090dfd98b947
diff --git a/src/doc/reference b/src/doc/reference
@@ -1 +1 @@
-Subproject commit 516549972d61c8946542d1a34afeae97167ff77b
+Subproject commit acedc32cacae80cf2f4925753a4ce7f7ffd7c86a
