syntax: Tidy up parsing the new attribute syntax

src/test/compile-fail/attr.rs

@@ -10,5 +10,5 @@
 
 fn main() {}
 
-#![lang(foo)] //~ ERROR An inner attribute was not permitted in this context.
-fn foo() {}
+#![lang(foo)] //~ ERROR an inner attribute is not permitted in this context
+fn foo() {}

src/test/compile-fail/column-offset-1-based.rs

@@ -8,4 +8,4 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-# //~ ERROR 11:1: 11:2 error: expected item
+# //~ ERROR 11:1: 11:2 error: expected `[` but found `<eof>`

src/test/compile-fail/issue-1655.rs

@@ -8,7 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-// error-pattern:expected item
+// error-pattern:expected `[` but found `~`
 mod blade_runner {
     #~[doc(
         brief = "Blade Runner is probably the best movie ever",