Add typings for the promise-hash library, v1.3 (#40331)

* Added typings for this promise-hash library

* pull out common type for the promise hash argument

* make recommended simplifications, expand test

types/promise-hash/index.d.ts

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+// Type definitions for promise-hash 1.3
+// Project: https://github.com/mtimofiiv/promise-hash
+// Definitions by: Michael Shafir <https://github.com/mshafir>
+// Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
+
+export = hash;
+
+type PromiseHash = <T>(promiseHash: { [P in keyof T]: PromiseLike<T[P]> | T[P] }) => Promise<T>;
+
+declare global {
+    interface PromiseConstructor {
+        hash: PromiseHash;
+    }
+}
+
+declare const hash: PromiseHash;

types/promise-hash/promise-hash-tests.ts

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+import hash = require('promise-hash');
+
+const result = Promise.hash({
+    a: 5,
+    b: Promise.resolve("test"),
+    c: Promise.hash({
+        d: Promise.resolve(true),
+        e: Promise.resolve("again")
+    })
+});
+
+type expectedType = Promise<{ a: number; b: string; c: { d: boolean; e: string; } }>;
+type resultIsExpected = typeof result extends expectedType ? true : false; // $ExpectType true
+type expectedIsResult = expectedType extends typeof result ? true : false; // $ExpectType true
+
+const dResult = result.then(x => x.c.d);
+dResult; // $ExpectType Promise<boolean>
+
+const result2 = hash({
+    test: Promise.resolve("hello world")
+});
+
+result2; // $ExpectType Promise<{ test: string; }>

types/promise-hash/tsconfig.json

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+{
+    "compilerOptions": {
+        "module": "commonjs",
+        "lib": [
+            "es6"
+        ],
+        "noImplicitAny": true,
+        "noImplicitThis": true,
+        "strictNullChecks": true,
+        "strictFunctionTypes": true,
+        "baseUrl": "../",
+        "typeRoots": [
+            "../"
+        ],
+        "types": [],
+        "noEmit": true,
+        "forceConsistentCasingInFileNames": true
+    },
+    "files": [
+        "index.d.ts",
+        "promise-hash-tests.ts"
+    ]
+}

types/promise-hash/tslint.json

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+{ "extends": "dtslint/dt.json" }