Neat trick.
There is one additional thing I would like to be able to do though: select a block of text and then use a keyboard shortcut (like CTRL-K/CTRL-C) to automatically insert the /*[textblock]*/ around the block (/*[textblock]--*/ would be even better!).
I wonder if anyone has tried to do this?
All the built-in ways I could find on the various menus and such in SSMS (including stuff not shown by default) seem to use the double-dash type comment. I have heard about third-party add-ins that add macro capability to SSMS that might prove useful.
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Just my $0.02 from over here in the cheap seats of the peanut gallery - please adjust for inflation and/or your local currency.