Cleanup "ts=Nightly", aka "ts=next" (microsoft#3156)

Author: rotu

packages/documentation/copy/en/release-notes/TypeScript 4.0.md

@@ -417,7 +417,7 @@ if (!obj.prop) {
 }
 ```
 
-[Try running the following example](https://www.typescriptlang.org/play?ts=Nightly#code/MYewdgzgLgBCBGArGBeGBvAsAKBnmA5gKawAOATiKQBQCUGO+TMokIANkQHTsgHUAiYlChFyMABYBDCDHIBXMANoBuHI2Z4A9FpgAlIqXZTgRGAFsiAQg2byJeeTAwAslKgSu5KWAAmIczoYAB4YAAYuAFY1XHwAXwAaWxgIEhgKKmoAfQA3KXYALhh4EA4iH3osWM1WCDKePkFUkTFJGTlFZRimOJw4mJwAM0VgKABLcBhB0qCqplr63n4BcjGCCVgIMd8zIjz2eXciXy7k+yhHZygFIhje7BwFzgblgBUJMdlwM3yAdykAJ6yBSQGAeMzNUTkU7YBCILgZUioOBIBGUJEAHwxUxmqnU2Ce3CWgnenzgYDMACo6pZxpYIJSOqDwSkSFCYXC0VQYFi0NMQHQVEA) to see how that differs from _always_ performing the assignment.
+[Try running the following example](https://www.typescriptlang.org/play?ts=next#code/MYewdgzgLgBCBGArGBeGBvAsAKBnmA5gKawAOATiKQBQCUGO+TMokIANkQHTsgHUAiYlChFyMABYBDCDHIBXMANoBuHI2Z4A9FpgAlIqXZTgRGAFsiAQg2byJeeTAwAslKgSu5KWAAmIczoYAB4YAAYuAFY1XHwAXwAaWxgIEhgKKmoAfQA3KXYALhh4EA4iH3osWM1WCDKePkFUkTFJGTlFZRimOJw4mJwAM0VgKABLcBhB0qCqplr63n4BcjGCCVgIMd8zIjz2eXciXy7k+yhHZygFIhje7BwFzgblgBUJMdlwM3yAdykAJ6yBSQGAeMzNUTkU7YBCILgZUioOBIBGUJEAHwxUxmqnU2Ce3CWgnenzgYDMACo6pZxpYIJSOqDwSkSFCYXC0VQYFi0NMQHQVEA) to see how that differs from _always_ performing the assignment.
 
 ```ts twoslash
 const obj = {

packages/playground-handbook/copy/en/TypeScript Versions.md

@@ -8,4 +8,4 @@ The dropdown shows the highest patch version for a TypeScript release, but that
 
 Setting a TypeScript version will append `?ts=[version]` to your URL and reload. For example, setting the TypeScript version to 4.3.5 will add `?ts=4.3.5` to the URL, which is an OK segue to the overview of the [URL's structure](/play#handbook-10).
 
-There's one special case where `?ts=Nightly` will find the latest version of the TypeScript which was built for the Playground and use that.
+There's one special case where `?ts=next` will find the latest version of the TypeScript which was built for the Playground and use that.

packages/playground-handbook/copy/en/URL Structure.md

@@ -26,9 +26,8 @@ Then the query string tend to be about changing the state of the Playground setu
 
   There are two special cases for the `ts` option:
 
-  - `ts=Nightly` where it will switch to most recently the nightly version.
-
-- `ts=dev` where it uses your [local developer's build of TypeScript](https://github.com/microsoft/TypeScript/blob/main/scripts/createPlaygroundBuild.js)
+  - `ts=next`: Use the most recent [nightly build](https://www.typescriptlang.org/docs/handbook/nightly-builds.html).
+  - `ts=dev`: Use your [local developer's build of TypeScript](https://github.com/microsoft/TypeScript/blob/main/scripts/createPlaygroundBuild.js)
 
 - `?flag=value` - Any compiler flag referenced in can be set from a query
 - `?filetype=js|ts|dts` - Tells the Playground to set the editor's language

packages/playground/README.md

@@ -37,8 +37,8 @@ Then queries tend to be about changing the state of the Playground setup from th
 
   There are two special cases for the `ts` option:
 
-  - `ts=Nightly` where it will switch to most recently the nightly version.
-  - `ts=dev` where it uses your [local developer's build of TypeScript](https://github.com/microsoft/TypeScript/blob/main/scripts/createPlaygroundBuild.js)
+  - `ts=next`: Use the most recent [nightly build](https://www.typescriptlang.org/docs/handbook/nightly-builds.html).
+  - `ts=dev`: Use your [local developer's build of TypeScript](https://github.com/microsoft/TypeScript/blob/main/scripts/createPlaygroundBuild.js)
 
 - `?flag=value` - Any compiler flag referenced in can be set from a query
 - `?filetype=js|ts|dts` - Tells the Playground to set the editor's type

packages/typescriptlang-org/src/pages/dev/bug-workbench.tsx

@@ -53,7 +53,7 @@ const Play: React.FC<Props> = (props) => {
 
       let tsVersionParam = params.get("ts")
       // handle the nightly lookup 
-      if (!tsVersionParam || tsVersionParam && tsVersionParam === "Nightly" || tsVersionParam === "next") {
+      if (!tsVersionParam || tsVersionParam === "Nightly" || tsVersionParam === "next") {
         // The CDN is configured to have a short TTL on the indexes directory.
         const nightlyLookup = await fetch("https://playgroundcdn.typescriptlang.org/indexes/next.json", { cache: "no-cache" })
         const nightlyJSON = await nightlyLookup.json()

packages/typescriptlang-org/src/templates/play.tsx

@@ -79,7 +79,7 @@ const Play: React.FC<Props> = (props) => {
 
       let tsVersionParam = params.get("ts")
       // handle the nightly lookup 
-      if (tsVersionParam && tsVersionParam === "Nightly" || tsVersionParam === "next") {
+      if (tsVersionParam === "Nightly" || tsVersionParam === "next") {
         // The CDN is configured to have a short TTL on the indexes directory.
         const nightlyLookup = await fetch("https://playgroundcdn.typescriptlang.org/indexes/next.json", { cache: "no-cache" })
         const nightlyJSON = await nightlyLookup.json()