docs, infra: cerebras docs, update docs template linting with better error (#25782)

docs/scripts/check_templates.py

@@ -66,19 +66,22 @@ def check_header_order(path: Path) -> None:
 
     with open(path, "r") as f:
         doc = f.read()
-    regex = r".*".join(headers)
-    if not re.search(regex, doc, re.DOTALL):
-        issueline = (
-            (
-                " Please see https://github.com/langchain-ai/langchain/issues/"
-                f"{issue_number} for instructions on how to correctly format a "
-                f"{doc_dir} integration page."
-            )
-            if isinstance(issue_number, int)
-            else ""
-        )
+    notfound = []
+    for header in headers:
+        index = doc.find(header)
+        if index == -1:
+            notfound.append(header)
+        doc = doc[index + len(header) :]
+    if notfound:
+        notfound_headers = "\n- ".join(notfound)
         raise ValueError(
-            f"Document {path} does not match the expected header order.{issueline}"
+            f"Document {path} is missing headers:"
+            "\n- "
+            f"{notfound_headers}"
+            "\n\n"
+            "Please see https://github.com/langchain-ai/langchain/issues/"
+            f"{issue_number} for instructions on how to correctly format a "
+            f"{doc_dir} integration page."
         )