[dcl.attr.grammar] Delete redundant "and no alignment-specifier".

Now that we say "an attribute-list with no attributes", the additional
"and no alignment-specifier" is redundant.

Author: tkoeppe

source/declarations.tex

@@ -9480,7 +9480,6 @@
 by an ellipsis is a pack expansion\iref{temp.variadic}.
 An \grammarterm{attribute-specifier} that contains
 an \grammarterm{attribute-list} with no \grammarterm{attribute}s
-and no \grammarterm{alignment-specifier}
 has no effect.
 The order in which the \grammarterm{attribute-token}{s} appear in an
 \grammarterm{attribute-list} is not significant. If a