Update welcome message

[kendfrey]

I've made some changes to the welcome message, including:

• Added a link to meta (culture)
• Reworded the "don't ask to ask", because that was hella confusing

Example can be seen at https://chat.stackoverflow.com/transcript/message/42342257#42342257

Feel free to berate me on the wording, or indeed to think that I did fine.

[benjamingr]

FWIW users already get a pretty big popup when they join chat apparently that tells them to report issues -

[Zirak]

Looks good, thanks! Just one small thing: could you just change the double quotes to singles?

[kendfrey]

@Zirak I purposely switched to double quotes because the string contains single quotes. Are you seriously suggesting it's better to have to escape them?

[Zirak]

@kendfrey That's the style guide, single quotes, for better and for worse.

[kendfrey]

In that case, you can expect a begrudging commit from me later today.

[Zirak]

Thanks @kendfrey!