Syntax lookup type coercion operator (#435)

Author: kevanstannard

misc_docs/syntax/operators_type_coercion.mdx

@@ -0,0 +1,69 @@
+---
+id: "type-coercion"
+keywords: ["operator", "type", "coercion", "polymorphic", "variant", "polyvar", "object"]
+name: ":>"
+summary: "This is the `type coercion` operator."
+category: "operators"
+---
+
+The `:>` operator may be used to convert a polymorphic variant to a `string` or `int`, or convert an [object](/docs/manual/latest/object) to a type with a subset of its fields.
+
+### Example 1
+
+<CodeTab labels={["ReScript", "JS Output"]}>
+
+```res
+type color = [#Red | #Green | #Blue]
+let color: color = #Red
+let message = "The color is " ++ (color :> string)
+```
+
+```js
+var message = "The color is Red";
+```
+
+</CodeTab>
+
+### Example 2
+
+<CodeTab labels={["ReScript", "JS Output"]}>
+
+```res
+type bit = [#0 | #1]
+let bit: bit = #1
+let value = (bit :> int)
+```
+
+```js
+var bit = 1;
+var value = 1;
+```
+
+</CodeTab>
+
+### Example 3
+
+<CodeTab labels={["ReScript", "JS Output"]}>
+
+```res
+type person = {"id": int, "name": string}
+type name = {"name": string}
+let person = {"id": 10, "name": "Gideon"}
+let name = (person :> name)
+```
+
+```js
+var person = {
+  id: 10,
+  name: "Gideon",
+};
+
+var name = person;
+```
+
+</CodeTab>
+
+
+### References
+
+* [Polymorphic Variant Coercion](/docs/manual/latest/polymorphic-variant#coercion)