[spec] Disagreement between the tests and the spec on the import of tags

[4y8]

The text format for importing tags (section 6.6.3, wasm-3.0) is (import mod:name nm:name (tag id? tt:tag)), where tag is defined as (tag id? x,I':typeuse) (section 6.6.8). A tag import, would thus require twice the tag keyword. It is not what is done in the test core/tag.wat :

  (import "test" "t3" (tag $t1 (param i32 f32)))

The tt : tag could be replaced by a typeuse or the definition of importdesc_I could be of the form ... | tag_I.