fix: add Intl.getCanonicalLocales type definition (#56079)

Co-authored-by: Nathan Shively-Sanders <293473+sandersn@users.noreply.github.com>

src/compiler/commandLineParser.ts

@@ -175,6 +175,7 @@ const libEntries: [string, string][] = [
     ["es2015.symbol", "lib.es2015.symbol.d.ts"],
     ["es2015.symbol.wellknown", "lib.es2015.symbol.wellknown.d.ts"],
     ["es2016.array.include", "lib.es2016.array.include.d.ts"],
+    ["es2016.intl", "lib.es2016.intl.d.ts"],
     ["es2017.date", "lib.es2017.date.d.ts"],
     ["es2017.object", "lib.es2017.object.d.ts"],
     ["es2017.sharedmemory", "lib.es2017.sharedmemory.d.ts"],

src/lib/es2016.d.ts

@@ -1,2 +1,3 @@
 /// <reference lib="es2015" />
 /// <reference lib="es2016.array.include" />
+/// <reference lib="es2016.intl" />

src/lib/es2016.intl.d.ts

@@ -0,0 +1,13 @@
+declare namespace Intl {
+    /**
+     * The `Intl.getCanonicalLocales()` method returns an array containing
+     * the canonical locale names. Duplicates will be omitted and elements
+     * will be validated as structurally valid language tags.
+     *
+     * [MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Intl/getCanonicalLocales)
+     *
+     * @param locale A list of String values for which to get the canonical locale names
+     * @returns An array containing the canonical and validated locale names.
+     */
+    function getCanonicalLocales(locale?: string | string[]): string[];
+}

src/lib/libs.json

@@ -30,6 +30,7 @@
         "es2015.symbol",
         "es2015.symbol.wellknown",
         "es2016.array.include",
+        "es2016.intl",
         "es2017.date",
         "es2017.object",
         "es2017.sharedmemory",