Recurring ambiguous "node number" wording still causes mistranslation (JA)

[yahonda]

What is changed, added or deleted? (Required)

In #20549 / #20811, "node number" was replaced with "node count" in tidb-cloud/size-your-cluster.md because "node number" reads as "the specific identification/label given to each instance" rather than "the quantity of instances". That fix was scoped to a single file, but the same ambiguous phrasing still appears throughout the corpus and has already caused at least one real Japanese mistranslation (release-notes-2023.md translated it as "ノード番号" / "node ID" instead of "ノード数" / "node count").

Remaining occurrences of "node number" (as of release-8.5) that likely need the same "node count" / "number of nodes" treatment:

• functions-and-operators/group-by-modifier.md:47 — link text [Change node number]
• tidb-cloud/backup-and-restore.md:312,340
• tidb-cloud/monitor-built-in-alerting.md:94-105 (12 occurrences, alert-rule table)
• tidb-cloud/releases/notification-2023-11-14-scale-feature-maintenance.md:22
• tidb-cloud/releases/release-notes-2023.md:901
• tidb-cloud/scalability-concepts.md:30,36,42
• tidb-cloud/scale-tidb-cluster.md:25,29,35 (including the ## Change node number heading)
• tidb-cloud/terraform-use-cluster-resource.md:268
• tidb-cloud/tiproxy-management.md:29 ("node numbers")

Suggest replacing with "node count" (matching the precedent in #20811) or "the number of ... nodes" for prose, and "Change node count" for the heading/link text.

Which TiDB version(s) do your changes apply to? (Required)

• master (the latest development version)

What is the related PR or file link(s)?

• Other reference link(s): follow-up to Replace node number with node count #20549 and Replace node number with node count #20811

Do your changes match any of the following descriptions?

• Delete files
• Change aliases
• Need modification after applied to another branch
• Might cause conflicts after applied to another branch