Move {3} inside | for SIGIL PROMOTER and TERMINATOR

[KronicDeth]

Fixes #674

Changelog

Enhancements

• Regression test for Broken highlighting when using sigils in arguments #674

Bug Fixes

• Move {3} inside | for SIGIL PROMOTER and TERMINATOR:

  SIGIL_HEREDOC_PROMOTER = ({SIGIL_DOUBLE_QUOTES_PROMOTER}|>
  {SIGIL_SINGLE_QUOTES_PROMOTER}){3}
  SIGIL_HEREDOC_TERMINATOR = ({SIGIL_DOUBLE_QUOTES_TERMINATOR}|>
  {SIGIL_SINGLE_QUOTES_TERMINATOR}){3}
  

  -- https://github.com/KronicDeth/intellij-elixir/blob/v5.1.0/src/org/elixir_lang/Elixir.flex?utf8=%E2%9C%93#L524-L525

  The | is inside group that is then {3}'d, so it allows either ' or " in groups of three. This is only applies to the sigils. It's correct for normal string and charlist heredocs:

  CHAR_LIST_HEREDOC_PROMOTER = {CHAR_LIST_PROMOTER}{3}
  CHAR_LIST_HEREDOC_TERMINATOR = {CHAR_LIST_TERMINATOR}{3}
  
  STRING_HEREDOC_PROMOTER = {STRING_PROMOTER}{3}
  STRING_HEREDOC_TERMINATOR = {STRING_TERMINATOR}{3}
  
  QUOTE_HEREDOC_PROMOTER = {CHAR_LIST_HEREDOC_PROMOTER} | {STRING_HEREDOC_PROMOTER}
  QUOTE_HEREDOC_TERMINATOR = {CHAR_LIST_HEREDOC_TERMINATOR} | {STRING_HEREDOC_TERMINATOR}
  

  -- https://github.com/KronicDeth/intellij-elixir/blob/v5.1.0/src/org/elixir_lang/Elixir.flex?utf8=%E2%9C%93#L441-L448