Highlight all unmarked code blocks in docstrings as Julia code

[mortenpi]

We already do this if the code block is the first element in the docstring, in order to support the common pattern where the function signature is in an indented code block

    foo()

Docs of foo...

However, it is not unreasonable to have multiple signatures in a docstring (see #1933 (comment)), and so it might be convenient to highlight them all. On the other hand, any non-Julia code block would need to get an explicit ```none. So I guess the question is which is more common in a docstring: multiple signatures or unhighlighted text blocks (hence the speculative label).

• It might make sense to distinguish indented vs non-indented code blocks, but we do not get that information from the parser as far as I know.
• It could also be implemented as an option (e.g. docstring_auto_highlight = :none, :first, :all, defaulting to :first).

Related issue: #1101

[odow]

Closing in favor of #1101