**Apache Airflow version**: 1.10.11

**Environment**: Python 3.7

- **Cloud provider or hardware configuration**:
- **OS** (e.g. from /etc/os-release): PRETTY_NAME="Debian GNU/Linux 10 (buster)"
 (from python3.7-slim-buster docker image)
- **Kernel** (e.g. `uname -a`): Linux 5.4.0-42-generic #46-Ubuntu SMP Fri Jul 10 00:24:02 UTC 2020 x86_64 GNU/Linux
- **Install tools**:
- **Others**:

**What happened**:

Using a markdown formatted table does not work.

**What you expected to happen**:

To be able to see a formated table within DAG view

**How to reproduce it**:

Add a tabular formatted code do dag.doc_md.

Example:

> mytable:
> 
> | a | b | c |
> | ------------- | ------------- | ------------- |
> | a | b | c |

[Table not formatted](https://i.imgur.com/l6JXuWe.png)

**Anything else we need to know**: N/A

tests/www/test_utils.py
self.check_generate_pages_html(current_page=0, total_pages=6)
    def test_generate_pager_current_middle(self):
        self.check_generate_pages_html(current_page=10, total_pages=20, check_middle=True)
    def test_generate_pager_current_end(self):
        self.check_generate_pages_html(current_page=38, total_pages=39)
    def test_params_no_values(self):
        """Should return an empty string if no params are passed"""
        self.assertEqual('', utils.get_params())
    def test_params_search(self):
        self.assertEqual('search=bash_', utils.get_params(search='bash_'))
    def test_params_none_and_zero(self):
        query_str = utils.get_params(a=0, b=None, c='true')
        
        pairs = list(sorted(query_str.split('&')))
        self.assertListEqual(['a=0', 'c=true'], pairs)
    def test_params_all(self):
        query = utils.get_params(status='active', page=3, search='bash_')
        self.assertEqual({'page': ['3'], 'search': ['bash_'], 'status': ['active']}, parse_qs(query))
    def test_params_escape(self):