Update article.md

Author: leviding

4-binary/04-file/article.md

@@ -61,8 +61,8 @@ The main methods:
 
 The choice of `read*` method depends on which format we prefer, how we're going to use the data.
 
-- `readAsArrayBuffer` - for binary files, to do low-level binary operations. For high-level operations, like slicing, `File` inherits from `Blob`, so we can call them directly, without reading.
-- `readAsText` - for text files, when we'd like to get a string.
+- `readAsArrayBuffer` -- for binary files, to do low-level binary operations. For high-level operations, like slicing, `File` inherits from `Blob`, so we can call them directly, without reading.
+- `readAsText` -- for text files, when we'd like to get a string.
 - `readAsDataURL` -- when we'd like to use this data in `src` for `img` or another tag. There's an alternative to reading a file for that, as discussed in chapter <info:blob>: `URL.createObjectURL(file)`.
 
 As the reading proceeds, there are events: