Edited ch12_mining.adoc with Atlas code editor

ch12_mining.adoc

@@ -567,7 +567,7 @@ version field set to 2 or higher) must contain the block height as a script
 === Constructing the Block Header
 
 To
-construct the block header, the mining node needs to fill in six fields,
+construct ((("bitcoins", "mining", "constructing block header", id="bitcoin-mining-blockheader")))((("mining", "constructing block header", id="mining-blockheader")))((("nodes", "miner nodes", "constructing block header", id="nodes-miner-blockheader")))((("block header", "constructing", id="block-header-construct")))the block header, the mining node needs to fill in six fields,
 as listed in <<block_header_structure_ch10>>.
 
 ++++
@@ -689,7 +689,7 @@ With all the other fields filled, the header of the candidate block is now compl
 the process of mining can begin. The goal is now to find a header
 that results in a hash that is less than the target.
 The mining node will need to test billions or trillions of variations of
-the header before a version is found that satisfies the requirement.
+the header before a version is found that satisfies the((("bitcoins", "mining", "constructing block header", startref="bitcoin-mining-blockheader")))((("mining", "constructing block header", startref="mining-blockheader")))((("nodes", "miner nodes", "constructing block header", startref="nodes-miner-blockheader")))((("block header", "constructing", startref="block-header-construct"))) requirement.
 
 === Mining the Block