chore: adds JSONPath Plus docs (#1694)

Co-authored-by: Nauman <[email protected]>

docs/getting-started/3-rulesets.md

@@ -29,6 +29,29 @@ Rules then target certain chunks of the JSON/YAML with the `given` keyword, whic
 
 The example above adds a single rule that looks at the root level `tags` object's children to make sure they all have a `description` property.
 
+### JSONPath Plus
+
+As mentioned, spectral is using JSONPath Plus which expands on the original JSONPath specification to add some additional operators and makes explicit some behaviors the original did not spell out.
+
+Here are some convenient **additions or elaborations**:
+
+- `^` for grabbing the **parent** of a matching item
+- `~` for grabbing **property names** of matching items (as array)
+- **Type selectors** for obtaining:
+  - Basic JSON types: `@null()`, `@boolean()`, `@number()`, `@string()`, `@array()`, `@object()`
+  - `@integer()`
+  - The compound type `@scalar()` (which also accepts `undefined` and
+    non-finite numbers when querying JavaScript objects as well as all of the basic non-object/non-function types)
+  - `@other()` usable in conjunction with a user-defined `otherTypeCallback`
+  - Non-JSON types that can nevertheless be used when querying
+    non-JSON JavaScript objects (`@undefined()`, `@function()`, `@nonFinite()`)
+- `@path`/`@parent`/`@property`/`@parentProperty`/`@root` **shorthand selectors** within filters
+- **Escaping**
+  - `` ` `` for escaping remaining sequence
+  - `@['...']`/`?@['...']` syntax for escaping special characters within
+    property names in filters
+- Documents `$..` (**getting all parent components**)
+
 ### Extending Rulesets
 
 Rulesets can extend other rulesets using the `extends` property, allowing you to pull in other rulesets.