Small fixups on the templates and create a checklist (WIP)

src/dynamic-import/assignment-expr-not-optional.case

src/dynamic-import/catch/nested-do-while.template

src/dynamic-import/catch/nested-do.template

src/dynamic-import/catch/nested-labeled-block.template

src/dynamic-import/checklist.md

...namic-import/default/nested-async-function-await.template

...mport/default/nested-async-function-return-await.template

src/dynamic-import/default/nested-async-function.template

src/dynamic-import/default/nested-do-while.template

src/dynamic-import/default/nested-do.template

src/dynamic-import/default/nested-labeled-block.template

src/dynamic-import/syntax/invalid/nested-do-while.template

src/dynamic-import/syntax/invalid/nested-do.template

src/dynamic-import/syntax/invalid/nested-labeled.template

src/dynamic-import/syntax/valid/nested-do-while.template

src/dynamic-import/syntax/valid/nested-do.template

src/dynamic-import/syntax/valid/nested-labeled.template