[Ada] Ensure No_Specification_Of_Aspect forbids pragmas and repr. clauses
gcc/ada/
* sem_ch13.adb (Analyze_Attribute_Definition_Clause): Add call
to Check_Restriction_No_Specification_Of_Aspect.
* sem_prag.adb (Analyze_Pragma): Likewise.
* restrict.ads (Check_Restriction_No_Specification_Of_Aspect):
Mention possible new node kinds in documentation.
* restrict.adb (Check_Restriction_No_Specification_Of_Aspect):
Retrieve aspect id from different fields if given node is an
N_Pragma or an N_Attribute_Definition_Clause.