feat(comment): comment on issues and pull requests the gh way

tea issue comment 12 --body "LGTM" failed with "unknown flag: --body"; the
comment had to be created with issue comment create. issue comment and
pr comment now take the issue or pull request and -b/-F/-e directly,
plus --edit-last and --delete-last for your last comment. The
subcommands stay, create is also add, and a misspelled subcommand
suggests the right one.

Comments are written in the configured editor or a multi-line
"Comment (markdown):" field, which edits start from the current text,
without a confirmation afterwards. The new comment's URL goes to stdout
with a ✓ line; deletes ask "Delete comment 81 on alice/x#1?". comment
list shows each comment under a "#79 alice • about 2 hours ago"
heading on a terminal and as key/value blocks when piped, and comment
JSON gains issue_number.

Signed-off-by: bircni <bircni@icloud.com>

internal/app/app_test.go

@@ -424,11 +424,6 @@ const (
 	issue attachment list
 	issue attachment upload
 	issue attachment view
-	issue comment create
-	issue comment delete
-	issue comment edit
-	issue comment list
-	issue comment view
 	label create
 	label delete
 	label edit
@@ -450,11 +445,6 @@ const (
 	pr attachment list
 	pr attachment upload
 	pr attachment view
-	pr comment create
-	pr comment delete
-	pr comment edit
-	pr comment list
-	pr comment view
 	search issue
 	search pr
 	time create
@@ -464,12 +454,10 @@ const (
 `
 	longsToWrite = `
 	issue attachment
-	issue comment
 	label
 	milestone
 	milestone issue
 	pr attachment
-	pr comment
 	time
 `
 )