Make conversions transitive and make getitem more comprehensive

Author: saulshanabrook

docs/changelog.md

@@ -21,6 +21,7 @@ _This project uses semantic versioning. Before 1.0.0, this means that every brea
   - Upgraded `egg-smol` dependency ([changes](https://github.com/saulshanabrook/egg-smol/compare/353c4387640019bd2066991ee0488dc6d5c54168...2ac80cb1162c61baef295d8e6d00351bfe84883f))
 
 - Add support for functions which mutates their args, like `__setitem__` [#35](https://github.com/metadsl/egglog-python/pull/35)
+- Makes conversions transitive
 
 ## 0.5.1 (2023-07-18)
 

docs/reference/egglog-translation.md

@@ -255,6 +255,8 @@ Math(2) + 30 + "x"
 Math(2) + Math(i64(30)) + Math.var(String("x"))
 ```
 
+Regstering a conversion from A to B will also register all transitively reachable conversions from A to B.
+
 ### Declarations
 
 In egglog, the `(declare ...)` command is syntactic sugar for a nullary function. In Python, these can be declare either as class variables or with the toplevel `egraph.constant` function: