Allow use any identifier for starting a simple heredoc
Allow use any identifier for starting a simple heredoc

Example:

    cat <<_ACEOF;
    #   ^^ keyword.operator.heredoc.shell
    #     ^^^^^^ keyword.control.heredoc-token.shell
        $variable
    # <- string.unquoted.heredoc.shell
    #   ^ punctuation.definition.variable.shell
    _ACEOF
    # <- keyword.control.heredoc-token.shell

jfcherng/Sublime-ShellScriptImproved