practice markdowns

_italic text_
**bold text**
- item1
- item2
- item21
- item22
# this is h1 tag
## this is h2 tag
### this is h3 tag
#### this is h4 tag
1. itemized 1
2. itemized 2
- itemized 21
- itemized 22

~~striked threough text~~
http://www.github.com/
#1

| First Header | Second Header |
| --- | --- |
| Content from cell 1 | Content from cell 2 |
| Content in the first column | Content in the second column |

The issue body contains rendered Markdown examples, but it names no file, test, entry point, or requested change. Review the issue as written first; the work is not complete until a concrete documentation goal and acceptance criteria are provided.

Written by the indexing model from the issue text.