Generators should escape correctly `@`.

[lu-zero]

Describe the bug Some targets do not accept @ as-is, so terms such as @id or @type have to be escaped/transformed.

To reproduce Steps to reproduce the behavior:

• Use a yaml containing @type, like https://github.com/w3c/wot-thing-description-toolchain-tmp/blob/main/src/thing_description_schema/schema/thing_description_schema.yaml
• Run poetry run gen-typescript on it.
• See the generated code sporting a @type? while it should be "@type"?

Expected behavior Every generator should have a mean to escape/map @terms.