get linkcheck clean

Author: steveklabnik

src/attributes.md

@@ -317,7 +317,7 @@ For any lint check `C`:
 
 The lint checks supported by the compiler can be found via `rustc -W help`,
 along with their default settings.  [Compiler
-plugins](../book/compiler-plugins.html#lint-plugins) can provide additional
+plugins](../unstable-book/plugin.html#lint-plugins) can provide additional
 lint checks.
 
 ```{.ignore}

src/macros.md

@@ -14,4 +14,4 @@ And one unstable way: [compiler plugins].
 
 [Macros]: ../book/macros.html
 [Procedural Macros]: ../book/procedural-macros.html
-[compiler plugins]: ../book/compiler-plugins.html
+[compiler plugins]: ../unstable-book/plugin.html