Add almost unique identifiers from pycardano 0.10.0

src/language_tour/classes.md

@@ -68,7 +68,7 @@ c = Animal(b"jackie", a)
 
 > Importantly, you need to set the `CONSTR_ID` of Classes that occur in a Union to distinct values.
 > On-Chain, classes are only distinguished by their `CONSTR_ID` value.
-> If omitted, the `CONSTR_ID` defaults to 0.
+> If omitted, the `CONSTR_ID` defaults to [an almost-unique determinstic value based on the Class definition](https://github.com/cardano-foundation/CIPs/pull/608).
 
 #### Type casts
 
@@ -126,4 +126,4 @@ This will return the `bytes` representing an object in CBOR.
 ```python
 print(a.to_cbor().hex())
 # prints "d8799f4542696c6c791907b2ff"
-```
+```