Update bip-0068.mediawiki

Fix typo.

Author: dooglus

bip-0068.mediawiki

@@ -43,7 +43,7 @@ This specification only interprets 16 bits of the sequence number as relative lo
 For time based relative lock-time, 512 second granularity was chosen because bitcoin blocks are generated every 600 seconds. So when using block-based or time-based, the same amount of time can be encoded with the available number of bits. Converting from a sequence number to seconds is performed by multiplying by 512 = 2^9, or equivalently shifting up by 9 bits.
 
 When the relative lock-time is time-based, it is interpreted as a minimum block-time constraint over the input's age. A relative time-based lock-time of zero indicates an input which can be included in any block. More generally, a relative time-based lock-time n can be included into any block produced 512 * n seconds after the mining date of the output it is spending, or any block thereafter.
-The mining date of the output is equals to the median-time-past of the previous block which mined it.
+The mining date of the output is equal to the median-time-past of the previous block which mined it.
 
 The block produced time is equal to the median-time-past of its previous block.