### Bug description

`quarto render index.qmd --to md` and `quarto render index.qmd --to markdown` produce different output.

### Steps to reproduce

Consider the minimal working example where `index.qmd` is

```
---
title: MWE
---

## Section
This is a simple placeholder for the manuscript's main document.
```

Run `quarto render index.qmd --to md --output md_output` and `quarto render index.qmd --to markdown --output markdown_output`.

Run `diff markdown_output md_output`.

### Expected behavior

`markdown_output` and `md_output` will be the same.

### Actual behavior

```
1,4c1
< ---
< title: MWE
< toc-title: Table of contents
< ---
---
> # MWE
8c5
< This is a simple placeholder for the manuscript's main document.
---
> This is a simple placeholder for the manuscript’s main document.
```

### Your environment

- Ubuntu

### Quarto check output

```
[✓] Checking versions of quarto binary dependencies...
      Pandoc version 3.1.2: OK
      Dart Sass version 1.55.0: OK
      Deno version 1.33.2: OK
[✓] Checking versions of quarto dependencies......OK
[✓] Checking Quarto installation......OK
      Version: 1.4.126
      Path: /opt/quarto/bin

[✓] Checking basic markdown render....OK

ERROR: YAMLError: unexpected end of the stream within a double quoted scalar at line 3, column 1:
    
    ^

Stack trace:
    
    ^
    at generateError (file:///opt/quarto/bin/quarto.js:10487:12)
    at throwError (file:///opt/quarto/bin/quarto.js:10490:11)
    at readDoubleQuotedScalar (file:///opt/quarto/bin/quarto.js:10836:12)
    at composeNode (file:///opt/quarto/bin/quarto.js:11309:125)
    at readBlockMapping (file:///opt/quarto/bin/quarto.js:11124:17)
    at composeNode (file:///opt/quarto/bin/quarto.js:11306:84)
    at readDocument (file:///opt/quarto/bin/quarto.js:11420:5)
    at loadDocuments (file:///opt/quarto/bin/quarto.js:11455:9)
    at load (file:///opt/quarto/bin/quarto.js:11460:23)
    at parse3 (file:///opt/quarto/bin/quarto.js:11470:12)
```
cscheid
2023-06-06T12:35:48Z
rgaiacs
enhancement pandoc
Future
open
md and markdown are different output formats - this is confusing
https://github.com/quarto-dev/quarto-cli/issues/5830