docs: fix ib-to-eb link for eb-chain

Author: will-break-it

docs/workshop/eb-chain.d2

@@ -137,11 +137,11 @@ eb_chain1.EB1 -> eb_chain1.IB2: "Ref" {
 }
 
 # IB validation references for Example 1
-eb_chain1.IB1 -> eb_chain1.EB1: "Validated against" {
+eb_chain1.IB1 -> eb_chain1.EB1: "Ledger Ref" {
   class: ledger_link
 }
 
-eb_chain1.IB2 -> eb_chain1.EB2: "Validated against" {
+eb_chain1.IB2 -> eb_chain1.EB2: "Ledger Ref" {
   class: ledger_link
 }
 
@@ -164,11 +164,11 @@ eb_chain2.EB3 -> eb_chain2.IB4: "Ref" {
 }
 
 # IB validation references for Example 2
-eb_chain2.IB3 -> eb_chain2.EB3: "Validated against" {
+eb_chain2.IB3 -> eb_chain2.EB3: "Ledger Ref" {
   class: ledger_link
 }
 
-eb_chain2.IB4 -> eb_chain2.EB4: "Validated against" {
+eb_chain2.IB4 -> eb_chain2.EB4: "Ledger Ref" {
   class: ledger_link
 }