(GH-538) Define schema extension methods

This change defines the `SchemaUtilityExtensions` trait in the
`dsc-lib-jsonschema` crate to provide useful shorthand methods for the
`schemars::Schema` type when munging and transforming schemas.

While the trait includes some methods I expect to be useful, it doesn't
try to fully map methods for retrieving every keyword. Instead, it
primarily simplifies working with the following keywords:

- `$id` to retrieve and set the identifier for a schema.
- `$defs` to retrieve and munge referenced subschemas.
- `properties` to retrieve and munge property definitions.

The trait _does_ define generic methods for retrieving keywords with an
expected type, like `get_keyword_as_object()` and `get_keyword_as_str`.
These are convenience methods to replace always calling code like the
following when you want to retrieve a keyword with a known type:

```rust
let ref schema = json_schema!({
    "title": "Schema title"
});
if let Some(title) = schema.get("title").and_then(|v| v.as_str()) {
    println!("Schema title is {title}");
}
```

So you can instead do:

```rust
let ref schema = json_schema!({
    "title": "Schema title"
});
if let Some(title) = schema.get_keyword_as_str("title") {
    println!("Schema title is {title}");
}
```

This change:

- Defines and implements the trait, providing documentation for every
  new method.
- Adds tests for the behaviors of every extension method.

Author: michaeltlombardi

Cargo.lock

@@ -198,7 +198,7 @@ tree-sitter-rust = { version = "0.24" }
 utfx = { version = "0.1" }
 # dsc-lib
 uuid = { version = "1.18", features = ["v4"] }
-# dsc-lib
+# dsc-lib, dsc-lib-jsonschema
 url = { version = "2.5" }
 # dsc-lib
 urlencoding = { version = "2.1" }

Cargo.toml

@@ -4,7 +4,7 @@ version = "0.0.0" # version stays 0.0.0 until we're ready to publish - should pi
 edition = "2024"
 
 [lib]
-doctest = false # Disable doc tests for compilation speed
+doctest = false # Disable doc tests by default for compilation speed
 
 [dependencies]
 regex = { workspace = true }
@@ -13,6 +13,7 @@ schemars = { workspace = true }
 serde = { workspace = true }
 serde_json = { workspace = true }
 tracing = { workspace = true }
+url = { workspace = true }
 
 [dev-dependencies]
 # Helps review complex comparisons, like schemas

lib/dsc-lib-jsonschema/Cargo.toml

@@ -8,8 +8,9 @@ use rust_i18n::i18n;
 #[macro_use]
 pub mod macros;
 
-pub mod vscode;
+pub mod schema_utility_extensions;
 pub mod transforms;
+pub mod vscode;
 
 #[cfg(test)]
 mod tests;