Use unsafeByteString instead of preEscapedText for ContentRaw

[alexbiehl]

This PR changes how we generate the code for Hamlet templates.

Currently we generate

             (asWidgetT . toWidget)
               ((preEscapedText . txt-2.1.1-d07d1290:Data.Text.Internal.pack)
                  " class="")

Note how we apply Data.Text.pack to the string literal. It works but we can be a little more direct at this point.

With this patch we are now generating leaner code that doesn't have to run pack during runtime and that with inlining can statically allocate the bytestring value (and possibly the Markup value):

       (asWidgetT . toWidget)
         (Text.Blaze.Internal.unsafeByteString
            (bytestring-0.12.2.0-5b16:Data.ByteString.Internal.Type.unsafePackLenLiteral
               51 "\"><p class=\"text-sm/6 font-semibold text-gray-900\">"#))

[alexbiehl]

Do you feel hesitant to go via some unsafeByteString? I am happy to make it use the lift instance of text values instead. Either way this is a minor but clear win.

[parsonsmatt]

This looks good to me - would you mind posting the before generated code too, just so we can see the difference?

Also please make a changelog note

Thanks!

[parsonsmatt]

Awesome, thank you!

I think usually pack gets inlined pretty well with string literals, but I do expect this form to require less compile-time work from the inliner, so it's definitely a performance win all around

[parsonsmatt]

2.1.7 uploaded!