pr_file_map.py: Use a human-readable date format (#15357)

* pr_file_map.py: Use a human-readable date format

Use a human-readable date format.

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

Author: cclauss

scripts/pr_file_map.py

@@ -15,7 +15,7 @@
 deleted, renamed, or on a branch not checked out locally).
 
 `DIRECTORY.md` is treated specially and reported in its own section at the very
-bottom. It is auto-generated, so nearly every PR touches it and it would
+bottom. It is auto-generated, so nearly every PR touches it, and it would
 otherwise dominate the "possible merge conflicts" list and distract busy
 maintainers. A merge conflict caused only by `DIRECTORY.md` is trivial to clear:
 choose __accept both__ in the GitHub UI. The bottom section therefore separates
@@ -37,8 +37,8 @@
 Requirements: gh (GitHub CLI), authenticated (`gh auth login`)
 
 Usage:
-    ./pr_file_map.py
-    ./pr_file_map.py > report.md
+    scripts/pr_file_map.py
+    scripts/pr_file_map.py > report.md
 """
 
 import json
@@ -101,7 +101,7 @@ def git_root() -> Path | None:
 def script_display_path() -> Path:
     """This script's path relative to the git root (falls back to absolute)."""
     script_path = Path(__file__).resolve()
-    if (root := git_root()) is not None:
+    if root := git_root():
         try:
             return script_path.relative_to(root.resolve())
         except ValueError:
@@ -179,7 +179,11 @@ def render_directory_section(
         f"### `{len(directory_only)}` PRs whose only overlap is "
         f"`{DIRECTORY_FILE}` (safe to accept both)\n"
     )
-    print(" ".join(f"#{n}" for n in directory_only) if directory_only else "_None._")
+    print(
+        "- " + ", ".join(f"#{n}" for n in directory_only)
+        if directory_only
+        else "_None._"
+    )
     print(
         f"\n### `{len(directory_plus_other)}` PRs that also overlap on other "
         "files (need a review or rebase)\n"
@@ -253,7 +257,7 @@ def main() -> None:
     # --- Render GitHub-flavored Markdown ---
     print("# Open Pull Request File Map\n")
     print(f"- Script: `{script_display_path()}`")
-    print(f"- Generated (UTC): `{datetime.now(UTC).isoformat()}`")
+    print(f"- Generated: `{datetime.now(UTC):%d %b %Y at %H:%M} {UTC}`")
     print(f"- Number of PRs: `{pr_count}`")
     print(f"- File touches (PR x file): `{touch_count}`")
     print(f"- Distinct files touched: `{distinct_count}`")