text into expressions and adds these to the cache. Note that
top-level comments are not cached because caching and in particular
checking if they are cached is too expensive. Comments may be cached as part
of the whole text (as opposed to on an expression by expression basis) using
cache_write() directly. Also, we must not cache stylerignore sequence,
because we might see the same expression that does not comply with the style
guide outside a stylerignore sequence and wrongly think we should leave it as
A character vector with one or more expressions.