R1:ebc2937dc89f

render_tag -> tag: final block

Summary:
Convert a final few `render_tag()` calls to `tag()` calls. This leaves us with 36 calls:

- 9 are in Conpherence, and will be converted after merging. Using Views makes the most sense here, to get access to renderHTMLView() and such.
- 2 are the definition and its library map entry.
- 3 are in the documentation.
- I believe the remaining 22 are too difficult to convert pre-merge. About half are in code which is slated for destruction; the other half are in…