Formatting errors and inconsistencies in several model files

This is very low priority as all the models in question function normally, but still something I intended on reporting.

There are several minor examples of these across certain model files:

• Especially in the case of those with item specifications, some missing spaces can be seen. For example, block/stairs.json is missing at least three; after the last 0 in the first translation, after the colon in the first scale, and after the 0 in the last translation.
• Very few models also use comments, for example block/fence_post.json. The vast majority of other models do not use these (for example piston_extended.json). It may be preferable to remove these comments as the provide no extra functionality and just bloat the jar.