[clang-tidy] Fix alphabetical order check for multiline doc entries and whitespace handling (#186950)

The `check_alphabetical_order.py` script previously only scanned the
first line of each bullet point in `ReleaseNotes.rst`, causing sorting
failures when a `:doc:` tag was split across multiple lines.

Also, when it is sorting the last entry of a section, the script will
insert an unnecessary whitespace.

This PR fixes these two problems.

clang-tools-extra/clang-tidy/tool/check_alphabetical_order.py

@@ -202,7 +202,7 @@ def find_heading(lines: Sequence[str], title: str) -> Optional[int]:
 
 def extract_label(text: str) -> str:
     if m := DOC_LABEL_RN_RE.search(text):
-        return m.group("label")
+        return m.group("label").strip()
     return text
 
 
@@ -221,7 +221,7 @@ def _parse_bullet_blocks(lines: Sequence[str], start: int, end: int) -> BulletBl
     blocks: List[BulletItem] = []
     res = _scan_bullet_blocks(lines, first_bullet, n)
     for _, block in res.blocks_with_pos:
-        key: CheckLabel = extract_label(block[0])
+        key: CheckLabel = extract_label("".join(block))
         blocks.append((key, block))
 
     suffix: Lines = list(lines[res.next_index : n])
@@ -294,16 +294,24 @@ def _find_section_bounds(
         if (h_end := find_heading(lines, next_title)) is None:
             # Scan forward to the next heading-like underline.
             h_end = sec_start
-            while h_end + 1 < len(lines):
-                if lines[h_end].strip() and set(lines[h_end + 1].rstrip("\n")) == {"^"}:
+            while h_end < len(lines):
+                if (
+                    h_end + 1 < len(lines)
+                    and lines[h_end].strip()
+                    and set(lines[h_end + 1].rstrip("\n")) == {"^"}
+                ):
                     break
                 h_end += 1
         sec_end = h_end
     else:
         # Scan to end or until a heading underline is found.
         h_end = sec_start
-        while h_end + 1 < len(lines):
-            if lines[h_end].strip() and set(lines[h_end + 1].rstrip("\n")) == {"^"}:
+        while h_end < len(lines):
+            if (
+                h_end + 1 < len(lines)
+                and lines[h_end].strip()
+                and set(lines[h_end + 1].rstrip("\n")) == {"^"}
+            ):
                 break
             h_end += 1
         sec_end = h_end

clang-tools-extra/clang-tidy/tool/check_alphabetical_order_test.py

@@ -109,6 +109,7 @@ class TestAlphabeticalOrderCheck(unittest.TestCase):
               <clang-tidy/checks/bugprone/easily-swappable-parameters>` check by
               correcting a spelling mistake on its option
               ``NamePrefixSuffixSilenceDissimilarityTreshold``.
+
             """
         )
         self.assertEqual(report_str, expected_report)
@@ -161,7 +162,6 @@ class TestAlphabeticalOrderCheck(unittest.TestCase):
 
                   Detect redundant parentheses.
 
-
                 """
             )
 
@@ -229,7 +229,6 @@ class TestAlphabeticalOrderCheck(unittest.TestCase):
                   exceptions from captures are now diagnosed, exceptions in the bodies of
                   lambdas that aren't actually invoked are not.
 
-
                 """
             )
             self.assertEqual(out, expected_out)
@@ -353,11 +352,52 @@ class TestAlphabeticalOrderCheck(unittest.TestCase):
 
               - ``for`` loops are supported.
 
-
            """
         )
         self.assertEqual(out, expected_out)
 
+    def test_release_notes_handles_multiline_doc(self) -> None:
+        rn_text = textwrap.dedent(
+            """\
+            Changes in existing checks
+            ^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+            - Renamed :doc:`performance-faster-string-find
+              <clang-tidy/checks/performance/faster-string-find>` to
+              :doc:`performance-faster-string-operation
+              <clang-tidy/checks/performance/faster-string-operation>`.
+              The `performance-faster-string-find` name is kept as an alias.
+
+            - Renamed :doc:`hicpp-no-assembler <clang-tidy/checks/hicpp/no-assembler>`
+              to :doc:`portability-no-assembler
+              <clang-tidy/checks/portability/no-assembler>`. The `hicpp-no-assembler`
+              name is kept as an alias.
+
+            """
+        )
+
+        out = _mod.normalize_release_notes(rn_text.splitlines(True))
+
+        expected_out = textwrap.dedent(
+            """\
+            Changes in existing checks
+            ^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+            - Renamed :doc:`hicpp-no-assembler <clang-tidy/checks/hicpp/no-assembler>`
+              to :doc:`portability-no-assembler
+              <clang-tidy/checks/portability/no-assembler>`. The `hicpp-no-assembler`
+              name is kept as an alias.
+
+            - Renamed :doc:`performance-faster-string-find
+              <clang-tidy/checks/performance/faster-string-find>` to
+              :doc:`performance-faster-string-operation
+              <clang-tidy/checks/performance/faster-string-operation>`.
+              The `performance-faster-string-find` name is kept as an alias.
+
+            """
+        )
+        self.assertEqual(out, expected_out)
+
     def test_process_checks_list_normalizes_output(self) -> None:
         list_text = textwrap.dedent(
             """\