I forgot to mention this in the earlier thread about spoiler tags. There's an extension called BBCode
that has most of the tags people use on forums, accessed in the right click menu. You can also add custom tags, like spoilers, custom images, etc.
So if you want to use spoilers without having to type the tags out, just install the extension, and it has settings in the bbcode right click menu. Click on BBCode -> Settings, then on the Custom Tags tab.
Then just select 1 in "Number of Custom Tags" and there will be an area for you to label the tag. Just put in "Spoilers" in the Label box, and
and click ok.
And that's it. Just select the text you want to spoiler tag, and select the tag in the bbcode right click menu. If you want to add more tags, just select how many you want to make, and there's a wiki that shows you how to make different kinds.