REPO_POLICIES: describe script/update-policy in its target's list item

The `make update-policy` item now names its script in the form of the
other targets, and the separate paragraph on `script/update-policy`
after the list of scripts with no required target is gone, as the
review at #159 (comment)
asks. `last_modified` is the date of this change.

Model: opus-5-5

prompts/REPO_POLICIES.md

@@ -1,6 +1,6 @@
 ---
 title: Repository Policies
-last_modified: 2026-11-09
+last_modified: 2026-11-15
 ---
 
 This document covers repository structure, tooling, and workflow standards. Code
@@ -102,7 +102,8 @@ where its implementation lives:
   `script/fmt-check`.
 - `make docker`: `script/docker`
 - `make hooks`: `script/install-precommit` installs the git pre-commit hook.
-- `make update-policy` (fetches the vendored policy files, commits and pushes)
+- `make update-policy`: `script/update-policy` fetches the vendored policy files
+  from the `prompts` repo, commits them and pushes.
 
 Three more scripts have no required target:
 
@@ -115,9 +116,6 @@ Three more scripts have no required target:
   Scripts that need the name call it, so they stay byte-identical across all
   repos. `script/docker`, for example, assembles its image tag from it.
 
-`script/update-policy` fetches the vendored policy files from the `prompts`
-repo, commits them and pushes. The `make update-policy` target shims to it.
-
 From the standard's canonical set we use `bootstrap`, `setup`, `test`, and
 `cibuild`. `check`, `precommit`, `install-precommit`, `update-policy` and
 `projectname` are our own extensions to the standard.