cssinfo: Back to data/master, wrap initial values in <code>

[jwhitlock]

In properties.json, initial can have three types of values:

1. A literal value, like 0 or 0% 0% or none, as seen on overflow.
2. A key into the localization strings file, as seen on -moz-appearance.
3. A list, each item which matches case 1 or 2.

Previously, case 1 (literal values) were designated with a <code> wrapper, and this was used in the MDN output. In mdn/data#52, the wrapper was removed, so there is no longer a distinction between case 1 or 2.

This PR uses the presence of the string in the localization strings as a way to distinguish between cases 1 and 2. If the string is not a localization key, a <code> wrapper is added for display. The PR also normalizes tabs to spaces.

Alternatively, a stronger method could be used in properties.json to distinguish between case 1 and 2.

Related to PR #132.

[Elchi3]

This works for me, and I'm happy that this brings us back to data/master.

We might change the implementation again, when there is a design decision in mdn/data#61 but I think we could go with this for now.

[jwhitlock]

I think mdn/data#61 is going to take a while to resolve. I also suspect that we'll need to release a versioned NPM package sooner rather than later, since the mdn/data schema and data model continues to evolve, and KS doesn't currently have a clean way to upgrade data usage w/o breakage. Merging.