Rollup merge of rust-lang#37194 - johnthagen:fix-const-static-header,…

… r=bluss

Remove un-rendered ticks from "const and static" doc title

Related to rust-lang#37116 and rust-lang#37119.

Ticks in the titles are not correctly rendered

![const-static-render](https://cloud.githubusercontent.com/assets/10340167/19412643/63e385a2-92e8-11e6-81f1-16802f803aad.png)

src/doc/book/const-and-static.md

@@ -1,4 +1,4 @@
-% `const` and `static`
+% const and static
 
 Rust has a way of defining constants with the `const` keyword: