Doc: use string array delimiter as-is input on highlight

[makenowjust]

Current highlighter implementation loses string array delimiter information, and replaces it with %w( or %i(. Highlighter should respect user input and it can produce invalid Crystal code if string array item has ).

For example, src/string_array.cr:

# ```
# %w[:-) ;)]
# ```
def string_array_example
end

and generated is:

Thank you.

[bcardiff]

Thanks @makenowjust