Fix broken links in the book.

src/doc/trpl/attributes.md

@@ -67,4 +67,4 @@ Rust attributes are used for a number of different things. There is a full list
 of attributes [in the reference][reference]. Currently, you are not allowed to
 create your own attributes, the Rust compiler defines them.
 
-[reference]: reference.html#attributes
+[reference]: ../reference.html#attributes

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

@@ -19,18 +19,16 @@ this reason.
 # `static`
 
 Rust provides a ‘global variable’ sort of facility in static items. They’re
-similar to [constants][const], but static items aren’t inlined upon use. This
-means that there is only one instance for each value, and it’s at a fixed
-location in memory.
+similar to constants, but static items aren’t inlined upon use. This means that
+there is only one instance for each value, and it’s at a fixed location in
+memory.
 
 Here’s an example:
 
 ```rust
 static N: i32 = 5;
 ```
 
-[const]: const.html
-
 Unlike [`let`][let] bindings, you must annotate the type of a `static`.
 
 [let]: variable-bindings.html

src/doc/trpl/raw-pointers.md

@@ -80,7 +80,7 @@ Raw pointers are useful for FFI: Rust’s `*const T` and `*mut T` are similar to
 C’s `const T*` and `T*`, respectfully. For more about this use, consult the
 [FFI chapter][ffi].
 
-[ffi]: ffi.md
+[ffi]: ffi.html
 
 # References and raw pointers
 

src/doc/trpl/unsafe.md

@@ -101,7 +101,7 @@ Rust has a feature called ‘`static mut`’ which allows for mutable global sta
 Doing so can cause a data race, and as such is inherently not safe. For more
 details, see the [static][static] section of the book.
 
-[static]: static.html
+[static]: const-and-static.html#static
 
 ## Dereference a raw pointer