feat: use $ instead of signal as exported function name

[dai-shi]

https://twitter.com/dai_shi/status/1606862972676354048

Well, thought it might not be a big change, but it looks cute.

[codesandbox-ci[bot]]

This pull request is automatically built and testable in CodeSandbox.

To see build info of the built libraries, click here or the icon next to each commit SHA.

Latest deployment of this branch, based on commit b06f468c136eaa591bc534ad5421b2450b57e9e0:

Sandbox	Source
React	Configuration
React Typescript	Configuration