* Add `Pear.badge(count)` documentation
Picked `null` to be the documented way to display a plain dot given it
coerces to `0`, so passes the `Number.isInteger(count)` check, and has
the same behavior in plain electron.
* Add `pear.stage.prefetch` to Application Configuration
* Update `stage` subcommand help output
The `truncate` was added since
https://github.com/holepunchto/pear/commit/85892a6a#diff-c218df6a550b0f3a42a2879e83f3ce2281061a1e79123d2a6d610d62d5f63bd8R79
but was missing.
* Add `pear.userAgent` to Application Configuration
* Adjust info about warmup in the guides
* Clarify that `pear.userAgent` will not change Sidecar requests
