Fix cyclic 'contains' relations

[digitalheir]

In signs_description.xml:

• Aa18 is a denoted to contain Aa17, but also vice versa. I think it is clear that Aa17 does not include Aa18.
• V98 is a denoted to contain V36, but also vice versa. I think it is clear that V98 does not include V36.
• Y1 is a denoted to contain Y2, but also vice versa. I think it is clear that Y2 does not include Y1.
• D32 is a denoted to contain D197, but also vice versa. I think it is clear that D197 does not include D32.

Additionally:

• I64 is a variant of I12, but I would not consider them as 'containing' each other
• Y4 is the mirror image of Y3, but I would not consider them as 'containing' each other