Closes#1042.
### What
`tea issue create`, `tea issue edit` and `tea pr create` all take the body via
`-d` / `--description`, but `tea comments add` and `tea comments edit` only
accepted it positionally — passing `-d` errored with
`flag provided but not defined: -d`.
This adds `-d` / `--description` to both `comments` subcommands so every
body-bearing command shares one flag.
### Behaviour / precedence
Unchanged for existing usage. Body resolution is now:
1. positional argument (kept first for back-compat),
2. `-d` / `--description`,
3. piped stdin,
4. `$EDITOR` (interactive only).
### Testing
- `go build`, `go vet ./...`, `go test -short ./cmd/... ./modules/...` all pass.
- Manually verified `tea comments add --help` / `edit --help` list the flag,
and that `-d` resolves the body (reaches the API, no parse error, no editor
prompt, no stdin block).
---------
Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>
Reviewed-on: https://gitea.com/gitea/tea/pulls/1043
Reviewed-by: Lunny Xiao <xiaolunwen@gmail.com>
Co-authored-by: Brien Coffield <coffbr01@gmail.com>
Co-committed-by: Brien Coffield <coffbr01@gmail.com>