Add error explanation for E0010

Author: robinst

src/librustc/diagnostics.rs

@@ -168,6 +168,11 @@ match x {
 ```
 "##,
 
+E0010: r##"
+The value of static and const variables must be known at compile time, and they
+live for the entire lifetime of a program. They can not use allocation.
+"##,
+
 E0015: r##"
 The only function calls allowed in static or constant expressions are enum
 variant constructors or struct constructors (for unit or tuple structs). This
@@ -459,7 +464,6 @@ a compile-time constant.
 }
 
 register_diagnostics! {
-    E0010,
     E0011,
     E0012,
     E0013,