Apparently missing function "string"

The documentation of `text` says

The document `(text s)` contains the literal string `s`. The string shouldn't contain any newline ('\n') characters. If the string contains newline characters, the function `string` should be used."

There is no `string` function in the API.

Locate the documentation for `text` and inspect the available API for handling strings containing newline characters. Confirm the intended function name from the implementation or exported API, then correct the reference and verify that the documentation no longer points to a missing function.

Written by the indexing model from the issue text.