How to use Generic String Delimiter ("|")

[Reza Nikoopour]

Hello All,

I'm trying to highlight a multiline construct.  It uses the here doc syntax

<<SYMBOL
whatever
text
SYMBOL

Do I need two delimiters as follows:

<<SYMBOL(1)
whatever
text(2)
SYMBOL

Or do I use one delimiter that spans the entire string body?

<<SYMBOL(delimiter start)
whatever
text(delimiter end)
SYMBOL

In my experiments using the single delimiter I've failed at getting the 

highlighting to work properly so I think I'm going down the wrong path.

I'm trying to avoid how sh-mode and the current implementation

of terraform-mode highlight the entirety of the closing SYMBOL.

Cheers,
Reza