apply one-sentence-per-line rule for rst files via github workflow.

.github/workflows/rst_check.yml

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+name: grammar / rule check for .rst files
+
+on:
+  pull_request:
+    paths:
+      - "**/*.rst" # trigger only for .rst files
+
+jobs:
+  one_sentence_per_line:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Setup Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: "3.10"
+
+      - name: Get changed lines in .rst files
+        run: |
+          git fetch origin ${{ github.base_ref }} --depth=1
+          git diff --unified=0 origin/${{ github.base_ref }} HEAD -- '*.rst' \
+            | grep '^[+-]' | grep -Ev '^(---|\+\+\+)' > /tmp/changed_lines.txt || true
+
+      - name: Run one-sentence-per-line checker on changed lines
+        run: |
+          python3 ./scripts/sentence_line_checker.py /tmp/changed_lines.txt

scripts/sentence_line_checker.py

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+# Copyright 2025 Sony Group Corporation.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+
+import argparse
+import re
+import sys
+
+def is_one_sentence_per_line(line) -> bool:
+    """
+    Check if a line contains only one complete sentence.
+
+    :param line: The line of file to check.
+    """
+    # this assumes a sentence ends with a period, question mark, or exclamation mark.
+    sentence_endings = re.findall(r'[.!?]', line)
+    # allow empty lines or lines with only one sentence
+    return len(sentence_endings) <= 1
+
+def check_changed_lines(filename) -> None:
+    """
+    Check only changed lines for violations.
+
+    .. warning:: It checks only added / modified lines for the viaolation in the file,
+       and ignores everything else including removed lines.
+
+    :param filename: The name of the file to check.
+    """
+    with open(filename, 'r', encoding='utf-8') as file:
+        lines = file.readlines()
+
+    violations = []
+    for lineno, line in enumerate(lines, start=1):
+        line = line.strip()
+        # check only added lines, ignore everything else
+        if line.startswith("+") and not is_one_sentence_per_line(line[1:]):
+            violations.append((lineno, line[1:]))
+
+    if violations:
+        print(f"\n⚠️ Found {len(violations)} violations: One sentence per line is required.")
+        for lineno, line in violations:
+            print(f"  ❌ Line {lineno}: {line}")
+        # exit with non-zero status code to fail github actions
+        sys.exit(1)
+    else:
+        print("✅ No violations found.")
+
+if __name__ == "__main__":
+    parser = argparse.ArgumentParser(
+        description="Check if modified contents contain only one complete sentence per line.")
+    parser.add_argument(
+        'filename', type=str, help='The name of the file to check.')
+    args = parser.parse_args()
+
+    check_changed_lines(args.filename)