feat(milestone): milestone tables, views, forms and one selection model

milestone view printed the list row, and milestone list hid the due date
and progress. milestone list now shows ID TITLE [STATE] DUE PROGRESS, open
milestones first and by due date; milestone view shows the state, due
date, progress, description and the milestone's web page (also --web).

Every milestone command addresses milestones by title or ID. Mutations
report ✓ lines: milestone create also prints the new milestone's URL and
takes the title as an argument; close and reopen skip milestones already
in that state; delete names the milestone in its confirmation; milestone
issue add and remove report one line such as "✓ Added #1, #2 to
milestone "v1.0" in alice/x". milestone issue list uses the issue table.
milestone edit without flags on a terminal opens the milestone form with
the current values, and every milestone command completes milestone
titles and has help text with examples.

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

internal/app/comments.go

@@ -26,14 +26,14 @@ type commentNouns struct {
 
 func commentWords(kind refKind) commentNouns {
 	if kind == pullRef {
-		return commentNouns{group: "pr", noun: "pull request", arguments: pullArguments, example: "13"}
+		return commentNouns{group: "pr", noun: "pull request", arguments: pullNumberArguments, example: "13"}
 	}
 	return commentNouns{group: "issue", noun: "issue", arguments: issueArguments, example: "12"}
 }
 
-// pullArguments is the ARGUMENTS help of pr comment and pr attachment commands, which take pull
+// pullNumberArguments is the ARGUMENTS help of pr comment and pr attachment commands, which take pull
 // request numbers like issue commands take issue numbers.
-const pullArguments = `A pull request can be supplied as argument in any of the following formats:
+const pullNumberArguments = `A pull request can be supplied as argument in any of the following formats:
 - by number, e.g. "13" or "#13"
 - by URL, e.g. "https://gitea.com/OWNER/REPO/pulls/13"
 - by repository and number, e.g. "OWNER/REPO#13"`