Replaced "brackets" with "parentheses"

...since the branch name *is* in parentheses, not brackets.

README.md

@@ -14,7 +14,7 @@ A [guide for astronauts](http://www.jsc.nasa.gov/news/columbia/fr_generic.pdf) (
 
 ### Conventions for this document
 
-For clarity's sake all examples in this document use customized bash prompt in order to indicate the current branch and whether or not there are staged changes. The branch is enclosed in brackets, and a `*` next to the branch name indicates staged changes.
+For clarity's sake all examples in this document use customized bash prompt in order to indicate the current branch and whether or not there are staged changes. The branch is enclosed in parentheses, and a `*` next to the branch name indicates staged changes.
 
 
 ## I need to add staged changes to the previous commit