set-alias-page.py: improve regex pattern (#14368)

scripts/set-alias-page.py

@@ -186,11 +186,21 @@ def get_alias_page(path: Path) -> str:
 
     if not path.exists():
         return ""
+
+    command_count = 0
+    command_name = ""
+
     with path.open(encoding="utf-8") as f:
         for line in f:
-            # match alias (`tldr <alias>`)
-            if match := re.search(r"^`tldr (.+)`", line):
-                return match[1]
+            # match alias page pattern "> This command is an alias of `example`."
+            if match := re.search(r"^> This command is an alias of `(.+)`\.$", line):
+                command_name = match[1]
+            # count the lines matching pattern "`...`"
+            if re.match(r"^`[^`]+`$", line.strip()):
+                command_count += 1
+
+    if command_count == 1:
+        return command_name
     return ""