Fix link and file name

Link redirected to 404, and since 10_1 isn't about building, I'm assuming the correct one to link to is 10_2: Building the Structure of P2SH.

Author: namcios

10_4_Scripting_a_Multisig.md

@@ -22,7 +22,7 @@ The requirement for that `0` as the first operand for `OP_CHECKMULTISIG` is a co
 
 ## Create a Raw Multisig 
 
-As discussed in [§10.1: Building a Bitcoin Script with P2SH](10_1_Building_a_Bitcoin_Script_with_P2SH.md), multisigs are one of the standard Bitcoin transaction types. A transaction can be created with a locking script that uses the raw `OP_CHECKMULTISIG` command, and it will be accepted into a block. This is the classic methodology for using multisigs in Bitcoin.
+As discussed in [§10.2: Building the Structure of P2SH](10_2_Building_the_Structure_of_P2SH.md), multisigs are one of the standard Bitcoin transaction types. A transaction can be created with a locking script that uses the raw `OP_CHECKMULTISIG` command, and it will be accepted into a block. This is the classic methodology for using multisigs in Bitcoin.
 
 As an example, we will revisit the multisig created in [§8.1](08_1_Sending_a_Transaction_to_a_Multisig.md) one final time and build a new locking script for it using this methodology. As you may recall, that was a 2-of-2 multisig built from `$address1` and `$address2`.