Jump classification fixes

[bcstrongx]

In section 4.1.1, the class of jumps that do use x0 as rd are listed as "Tail-calls":

Tail-calls:
– jal x0;
– c.j;
– jalr x0, rs where rs != x1 and rs != x5;
– c.jr rs1 where rs1 != x1 and rs1 != x5.

Also, in table 4.4, encodings 10 & 11 refer to tail-calls. These should be referred to simply as jumps, as discussed in the trace TG.

Further, in section 4.1.1, "jal x0" seems to fall into both the "Tail-call" category, as well as the "Other" category:

Tail-calls:
– jal x0;

Other:
– jal rd where rd != x1 and rd != x5;

"Other" should add "rd != x0" as well.