Rollup merge of #43240 - steveklabnik:update-books, r=QuietMisdreavus

frewsxcv · web-flow · commit e3825ecd4c4e · 2017-07-14T20:57:19.000-07:00
Update the books.

`python x.py test src\doc` passes on my machine.
diff --git a/src/doc/book b/src/doc/book
@@ -1 +1 @@
-Subproject commit 325c3da0814f44916bef00ff225f934f2d613203
+Subproject commit 4ee596df22f8ecaa9a0b2ddc0624b0104540dbf7
diff --git a/src/doc/nomicon b/src/doc/nomicon
@@ -1 +1 @@
-Subproject commit eee5ffb12773469bc02895d6b5e7e663b3a572a2
+Subproject commit 81134a4dff811403b3b2f349b0c59a819f0fe0c1
diff --git a/src/doc/reference b/src/doc/reference
@@ -1 +1 @@
-Subproject commit 876582e9d0fbdc9cecb03133c28db96e9ff8c844
+Subproject commit 1abfbaa70313fdf527cf799ffd9b9a096a62105c
