Added test for check doc strings in crates.

#1856

crates/ra_hir/src/lib.rs

@@ -1,5 +1,3 @@
-#![recursion_limit = "512"]
-
 //! HIR (previously known as descriptors) provides a high-level object oriented
 //! access to Rust code.
 //!
@@ -7,6 +5,8 @@
 //! to a particular crate instance. That is, it has cfg flags and features
 //! applied. So, the relation between syntax and HIR is many-to-one.
 
+#![recursion_limit = "512"]
+
 macro_rules! impl_froms {
     ($e:ident: $($v:ident $(($($sv:ident),*))?),*) => {
         $(