Fix Typo: Hash Time Locked Contract (#662)

preface.asciidoc

@@ -200,6 +200,7 @@ Following is an alphabetically sorted list of all the GitHub contributors, inclu
 * Ricardo Marques (@RicardoM17)
 * Sergei Tikhomirov (@s-tikhomirov)
 * Simone Bovi (@SimoneBovi)
+* Taylor Masterson (@tjmasterson)
 * Umar Bolatov (@bolatovumar)
 
 Without the help offered by everyone listed above, this book would not have been possible. Your contributions demonstrate the power of open source and open culture, and we are eternally grateful for your help.

routing.asciidoc

@@ -40,7 +40,7 @@ This enables fans to use intermediary nodes to pay Dina, without leaking private
 This process of connecting a series of payment channels with end-to-end security, and the incentive structure for nodes to _forward_ payments, is one of the key innovations of the Lightning Network.
 
 In this chapter, we'll dive into the mechanism of routing in the Lightning Network, detailing the precise manner in-which payments flow through the network.
-First, we will cover the concept of a conditional chained end-to-end secure payment, most commonly referred to as a Hash Time Locked Transaction (HTLC).
+First, we will cover the concept of a conditional chained end-to-end secure payment, most commonly referred to as a Hash Time Locked Contract (HTLC).
 Having learned how payments can be transmitted through the network, we will then discuss the concept of source-based routing and contrast it to the privacy preserving onion routing used in the network today.
 Finally, we will explore the exact mechanism of payment forwarding.
 We will discuss how the _structure_ (edges, fees, time-locks, etc) of the route is determined by the sender, and is then transmitted to each individual node along the route.