Merge pull request #1856 from petk/patch-sentence

Fix closing bracket

book/07-git-tools/sections/revision-selection.asc

@@ -74,10 +74,8 @@ If you try to check out that object again at some point, you'll always get the d
 
 However, you should be aware of how ridiculously unlikely this scenario is.
 The SHA-1 digest is 20 bytes or 160 bits.
-The number of randomly hashed objects needed to ensure a 50% probability of a single collision is about 2^80^
-(the formula for determining collision probability is `p = (n(n-1)/2) * (1/2^160))`. 2^80^
-is 1.2 x 10^24^
-or 1 million billion billion.
+The number of randomly hashed objects needed to ensure a 50% probability of a single collision is about 2^80^ (the formula for determining collision probability is `p = (n(n-1)/2) * (1/2^160)`).
+2^80^ is 1.2 x 10^24^ or 1 million billion billion.
 That's 1,200 times the number of grains of sand on the earth.
 
 Here's an example to give you an idea of what it would take to get a SHA-1 collision.