Add titleSuffix as future replacement for header.organisationName option

[frankieroberto]

This moves the organisationName config option out from the header config option to be a top-level config option named titleSuffi, as it is now only used in the title tag.

To avoid a breaking change, header.organisationName is still supported a fallback. This could be removed in a future breaking change release.

Additionally, if both titleSuffix and header.organisationName are set to false, then the - will not be added to the title tag (for scenarios where an title suffix might not be needed).

[frankieroberto]

As well as moving this option, it could be renamed to something like titleSuffix, which might make it a bit clearer what it does? (Also I guess strictly speaking GOV.UK isn't an organisation).

[paulrobertlloyd]

I think titleSuffix makes sense.

Do we need to keep header.organisationName given that, in theory, this value is no longer supported in v6?

[frankieroberto]

I think titleSuffix makes sense.

Do we need to keep header.organisationName given that, in theory, this value is no longer supported in v6?

If we remove it and anyone has set a custom suffix, then it’ll revert back to - GOV.UK, which feels like a kinda breaking change? Although maybe it’s low risk and we could do a search to see if this affects anyone?

[frankieroberto]

I've renamed to titleSuffix but kept the backwards-compatibility for now. But feel free to remove that if you don’t think it’ll affect anyone significantly.

[paulrobertlloyd]

Maybe we keep the backwards compatibility for now, and remove in v7. We can add an issue and assign it to the v7.0 milestone. I’m expecting that to have a number of breaking changes, given it will change how layouts are loaded from the plugin (and likely see a move to ES module syntax, too).