Requested move: x_gundam -> gundam_x_(mobile_suit)

Because it's the correct name.

Series name is wrong too so we could move gundam_x to after_war_gundam_x and x_gundam to gundam_x.

That works too.

Ah, swapping two tags around (rather than aliasing them to new ones) is always messy though... like the Street Fighter issue. Well it's not a huge tag so I'll go with it.