docs: the tasks manual points task.parallel at Tasks, not Spending (#1454)

docs/changes/unreleased/1886-tasks-at-once-manual-category.md

@@ -0,0 +1,8 @@
+---
+kind: fixed
+title: the tasks manual points task.parallel at Tasks, not Spending
+pr: 1886
+surface: [docs]
+invalidates:
+  - "The tasks manual located `task.parallel` under the settings panel's category \"spending\", so someone following the page searched the wrong section. `/settings` draws the row under Tasks as `tasks at once` (`CategoryTasks` in the registry); the page now names the section and the row exactly as drawn, and manual probes for the setting reach the tasks page."
+---

internal/manual/chat/tasks.md

@@ -4350,13 +4350,13 @@ The plan store allows up to 256 tasks in one added batch and 1024 tasks in one r
 A composite worker can wake at most four times to integrate its children. The node
 tree's 3/20 bounds do not apply to that run.
 
-## How many tasks run at once — can I have it do two things at the same time, can you work on several parts of my answer at once
+## How many tasks run at once, where is task.parallel, where is the tasks at once setting, can I have it do two things at the same time, can you work on several parts of my answer at once
 
 **There is no limit by default.** codeaf does not cap the number of tasks running at the
 same time.
 
 The setting `task.parallel` exists for anyone who wants a number anyway — settings panel
-(`ctrl+,` or `/settings`), category "spending". Blank means no limit. A cap is a queue and
+(`ctrl+,` or `/settings`), under Tasks as `tasks at once`. Blank means no limit. A cap is a queue and
 never a refusal: work past the cap waits and starts when a slot frees, and while it waits
 its roster row says `waiting · slot` on its hint line, and it sits under `Queued`, which
 starts folded to its heading.

internal/manual/chat_test.go

@@ -841,6 +841,8 @@ func TestTheChatManualAnswersTheQuestionsPeopleAsk(t *testing.T) {
 		{"my cursor jumped to another task while I was reading", "tasks"},
 		{"why is the finished piece at the bottom of the family", "tasks"},
 		{"can codeaf parallelize my task", "tasks"},
+		{"where is the tasks at once setting", "tasks"},
+		{"what section is task.parallel under", "tasks"},
 		{"how do I open my tasks on a phone", "tasks"},
 		{"how do I get back from a task on my phone", "tasks"},
 		{"do tasks touch my working copy", "how-tasks-run"},
@@ -3312,6 +3314,29 @@ func TestTheChatManualAnswersTheQuestionsPeopleAsk(t *testing.T) {
 	}
 }
 
+// #1454: task.parallel is on the Tasks tab as `tasks at once`, not under
+// Spending. This checks the retrieved section's answer rather than only its
+// page, so restoring the former category cannot leave the retrieval gate green.
+func TestTaskParallelQuestionReachesItsCorrectedSettingsLocation(t *testing.T) {
+	const (
+		question = "where is task.parallel"
+		title    = "How many tasks run at once"
+	)
+	for _, section := range Chat().Search(question, DefaultResults) {
+		if section.Page != "tasks" || !strings.Contains(section.Title, title) {
+			continue
+		}
+		if !strings.Contains(section.Body, "under Tasks as `tasks at once`") {
+			t.Errorf("task.parallel answer omits its visible settings location: %s", section.Body)
+		}
+		if strings.Contains(section.Body, `category "spending"`) {
+			t.Errorf("task.parallel answer still names the former category: %s", section.Body)
+		}
+		return
+	}
+	t.Fatalf("%q did not reach tasks · %q", question, title)
+}
+
 // #1469: home listed waiting standing orders without their due time, and a person
 // asking when one goes off there had to be sent to the standing place for it.
 // Standing orders are automations now (automations.md), and home's `automations`