Update the help text and flag description for `gh release upload --clobber`
to make it clear that existing assets are deleted before new ones are uploaded,
and that original assets will be lost if the upload fails.
Fixes#8822
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
The formatting verb is used incorrectly and produces a misleading
help text for this command:
```
To define a display label for an asset, append text starting with %#% after the file name.
```
instead of the expected:
```
To define a display label for an asset, append text starting with `#` after the file name.
```
This changes the FetchRelease implementation to look up draft releases directly using by its pending tag name, as opposed to resorting to the Releases list API which is backed by Elastic Search and thus suffers replication lag after the creation of a draft release.
Bonus: all release lookup functions now accept a context for cancellation.
