File level documentation is not generated

The Writing Documentation section in the README says:

Messages, Fields, Services (and their methods), Enums (and their values), Extensions, and Files can be documented.

However when rendering a file with file-level documentation, that documentation is not rendered.

Example (at the file-level trying 2 different comment formats at the time, trying with one at the time doesn't help either):

// Test docs for the file

/** Test docs for the file */

syntax = "proto3";

// Test docs for the package
package testdocs;

// A test message
message TestDocs {
  // A test ID
  uint64 id = 1;
}

docker run --rm -v/tmp/test:/tmp/test pseudomuto/protoc-gen-doc \
    -I/tmp/test --doc_opt=markdown,test.md --doc_out=/tmp/test /tmp/test/test.proto

/tmp/test/test.md:

# Protocol Documentation
<a name="top"></a>

## Table of Contents

- [test.proto](#test-proto)
    - [TestDocs](#testdocs-TestDocs)

- [Scalar Value Types](#scalar-value-types)

<a name="test-proto"></a>
<p align="right"><a href="#top">Top</a></p>

## test.proto

<a name="testdocs-TestDocs"></a>

### TestDocs
A test message

| Field | Type | Label | Description |
| ----- | ---- | ----- | ----------- |
| id | [uint64](#uint64) |  | A test ID |

## Scalar Value Types

| .proto Type | Notes | C++ | Java | Python | Go | C# | PHP | Ruby |
| ----------- | ----- | --- | ---- | ------ | -- | -- | --- | ---- |
| <a name="double" /> double |  | double | double | float | float64 | double | float | Float |
| <a name="float" /> float |  | float | float | float | float32 | float | float | Float |
| <a name="int32" /> int32 | Uses variable-length encoding. Inefficient for encoding negative numbers – if your field is likely to have negative values, use sint32 instead. | int32 | int | int | int32 | int | integer | Bignum or Fixnum (as required) |
| <a name="int64" /> int64 | Uses variable-length encoding. Inefficient for encoding negative numbers – if your field is likely to have negative values, use sint64 instead. | int64 | long | int/long | int64 | long | integer/string | Bignum |
| <a name="uint32" /> uint32 | Uses variable-length encoding. | uint32 | int | int/long | uint32 | uint | integer | Bignum or Fixnum (as required) |
| <a name="uint64" /> uint64 | Uses variable-length encoding. | uint64 | long | int/long | uint64 | ulong | integer/string | Bignum or Fixnum (as required) |
| <a name="sint32" /> sint32 | Uses variable-length encoding. Signed int value. These more efficiently encode negative numbers than regular int32s. | int32 | int | int | int32 | int | integer | Bignum or Fixnum (as required) |
| <a name="sint64" /> sint64 | Uses variable-length encoding. Signed int value. These more efficiently encode negative numbers than regular int64s. | int64 | long | int/long | int64 | long | integer/string | Bignum |
| <a name="fixed32" /> fixed32 | Always four bytes. More efficient than uint32 if values are often greater than 2^28. | uint32 | int | int | uint32 | uint | integer | Bignum or Fixnum (as required) |
| <a name="fixed64" /> fixed64 | Always eight bytes. More efficient than uint64 if values are often greater than 2^56. | uint64 | long | int/long | uint64 | ulong | integer/string | Bignum |
| <a name="sfixed32" /> sfixed32 | Always four bytes. | int32 | int | int | int32 | int | integer | Bignum or Fixnum (as required) |
| <a name="sfixed64" /> sfixed64 | Always eight bytes. | int64 | long | int/long | int64 | long | integer/string | Bignum |
| <a name="bool" /> bool |  | bool | boolean | boolean | bool | bool | boolean | TrueClass/FalseClass |
| <a name="string" /> string | A string must always contain UTF-8 encoded or 7-bit ASCII text. | string | String | str/unicode | string | string | string | String (UTF-8) |
| <a name="bytes" /> bytes | May contain any arbitrary sequence of bytes. | string | ByteString | str | []byte | ByteString | string | String (ASCII-8BIT) |

Neither the file or package documentation is to be seen.

pseudomuto / protoc-gen-doc

File level documentation is not generated #525