signature: Defining KeyLocator as an optional field in generic SignatureInfo

Change-Id: I2e2850bdf5b1795c07aea208fe8c80c8b6df509f
diff --git a/tlv.rst b/tlv.rst
index 1bf28c4..0182f36 100644
--- a/tlv.rst
+++ b/tlv.rst
@@ -81,7 +81,7 @@
 TLV Encoding
 ~~~~~~~~~~~~
 
-TLV encoding for NDN pakcets is defined as follows::
+TLV encoding for NDN packets is defined as follows::
 
      NDN-TLV := TLV-TYPE TLV-LENGTH TLV-VALUE?
      TLV-TYPE := VAR-NUMBER