Jason Song 4ae3f76217
Deal with markdown template without metadata (#21639)
Fixed #21636.

Related to #20987.

A markdown template without metadata should not be treated as an invalid
template.

And this PR fixed another bug that non-template files(neither .md nor
.yaml) are treated as yaml files.

<img width="504" alt="image"
src="https://user-images.githubusercontent.com/9418365/198968668-40082fa1-4f25-4d3e-9b73-1dbf6d1a7521.png">
2022-10-31 17:10:33 +02:00
..
2020-08-24 11:48:15 -04:00
2022-09-29 05:27:33 +02:00
2022-03-30 16:42:47 +08:00
2021-06-17 18:04:10 +02:00
2021-10-25 11:43:40 +08:00
2021-06-29 16:28:38 +02:00