Add a table with tested formats

serdect/README.md

@@ -29,6 +29,18 @@ While this crate can't ensure that format implementations don't perform
 other kinds of data-dependent branching on the contents of the serialized data,
 using a constant-time hex serialization with human-readable formats should
 help reduce the overall timing variability.
+The table below lists the formats `serdect` is tested against, and
+whether the serialization via `array` or `slice` is constant-time for them.
+
+| Format                          | `array`  | `slice`  |
+|---------------------------------|----------|----------|
+| Bincode (`bincode=^1`)          | ✅ | ✅ |
+| CBOR (`ciborium=^0.2`)          | ❌ | ✅ |
+| MessagePack (`rmp-serde`)       | ❌ | ✅ |
+| JSON (`serde-json-core=^0.5`)   | ✅ | ✅ |
+| JSON (`serde-json=^1`)          | ✅ | ✅ |
+| TOML (`toml=^0.7`)              | ✅ | ✅ |
+
 
 ## Minimum Supported Rust Version