GoogleBlogs: “In Google Docs, you can now select “Automatically detect Markdown” from Tools > Preferences to enable auto correcting for Markdown syntax, a lightweight markup language for applying formatting using plain text. Currently, Google Docs supports some Markdown syntax, such as:

•  * or – followed by a space autocorrects to bullet points
• Various ways to start a numbered list similar to Markdown
• [] followed by a space autocorrects to checkboxes

The expanded support will now support autocorrection for:

1. Headings
2. Italic and bold
3. Bold + italic
4. Strikethrough
5. Links