fix: address verified review findings (issues-1)

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

internal/app/completion.go

@@ -383,7 +383,8 @@ func (a *application) completeLabels() cobra.CompletionFunc {
 	}))
 }
 
-// completeMilestones completes the titles of open milestones.
+// completeMilestones completes the titles of open milestones. A numeric title would be read as
+// another milestone's ID, so such a milestone is completed by its own ID instead.
 func (a *application) completeMilestones() cobra.CompletionFunc {
 	return a.completeMilestonesIn("open")
 }
@@ -392,7 +393,13 @@ func (a *application) completeMilestones() cobra.CompletionFunc {
 func (a *application) completeMilestonesIn(state string) cobra.CompletionFunc {
 	return a.apiCompletion(true, func(ctx context.Context, t target, _ string) ([]cobra.Completion, error) {
 		items, err := services.Milestones{Client: t.client, Repository: t.Repo}.List(ctx, state, completionLimit, 1)
-		return describe(items, func(item services.Milestone) (string, string) { return item.Title, item.Description }), err
+		return describe(items, func(item services.Milestone) (string, string) {
+			// A title that reads as a number would be taken as an ID, so offer the ID instead.
+			if _, parse := strconv.ParseInt(strings.TrimSpace(item.Title), 10, 64); parse == nil {
+				return strconv.FormatInt(item.ID, 10), strings.TrimSpace(item.Title + " " + item.Description)
+			}
+			return item.Title, item.Description
+		}), err
 	})
 }