Fix documentation of basic stack protector

A stack protector is used for N >= 8, not N > 8.

compiler/rustc_codegen_llvm/src/lib.rs

@@ -304,8 +304,8 @@ fn print(&self, req: PrintRequest, sess: &Session) {
           local stack variable in the ABI.)
 
     basic
-        Generate stack canaries in functions with:
-        - local variables of `[T; N]` type, where `T` is byte-sized and `N` > 8.
+        Generate stack canaries in functions with local variables of `[T; N]`
+        type, where `T` is byte-sized and `N` >= 8.
 
     none
         Do not generate stack canaries.