Hilighting heredoc in Array is not rendered correctfully

[sevenc-nanashi]

[Describe your issue here. Try to be as specific as possible so we can find the root cause more quickly!]

Steps to reproduce

1. Set redcarpet as parser
2. Create new file
3. Write like:

`` `ruby
[
  ["Some", <<~EOS],
    some text
  EOS
  ["Some", <<~EOS]
    some text
  EOS
]
`` `

(Please delete space inside triple backquotes.)

Actual Output

Expected Output

Environment details:

• OS: Windows 10
• Ruby version (ruby -v): ruby 3.0.2p107 (2021-07-07 revision 0db68f0233) [i386-mingw32]
• YARD version (yard -v): yard 0.9.26
• Relevant software dependency/versions:
  • redcarpet

I have read the Contributing Guide.

[lsegal]

It's possible that this was fixed by #1389, in which case this will be available in the next release. You can check by pulling that branch or testing from the main branch.