docs: capitalize 'S' in TypeScript (#752)

- also capitalize 'S' in JavaScript for consistency

- reword a confusing comment in the codebase that mentioned
  "typescript types" (and hence showed up on regex search) to
  more accurate "type declarations" phrasing
  - this seems to have been added in the early days of TSDX,
    in commit 6bbf077

Co-Authored-By: Orta Therox <orta.therox+github@gmail.com>

Co-authored-by: Anton Gilgur <agilgur5@gmail.com>

CONTRIBUTING.md

@@ -17,7 +17,7 @@ Thanks for your interest in TSDX! You are very welcome to contribute. If you are
    cd tsdx
    ```
 
-1. Install the dependencies and build the Typescript files to Javascript:
+1. Install the dependencies and build the TypeScript files to JavaScript:
 
    ```
    yarn && yarn build

README.md

@@ -72,7 +72,7 @@ yarn start
 _Requires Node `>= 10`._
 
 
-That's it. You don't need to worry about setting up Typescript or Rollup or Jest or other plumbing. Just start editing `src/index.ts` and go!
+That's it. You don't need to worry about setting up TypeScript or Rollup or Jest or other plumbing. Just start editing `src/index.ts` and go!
 
 Below is a list of commands you will probably find useful:
 

src/deprecated.ts

@@ -26,7 +26,7 @@ export async function moveTypes() {
       'caused declarations to be unnecessarily created for test files.'
   );
 
-  // Move the typescript types to the base of the ./dist folder
+  // Move the type declarations to the base of the ./dist folder
   await fs.copy(appDistSrc, paths.appDist, {
     overwrite: true,
   });

website/pages/index.mdx

@@ -29,7 +29,7 @@ You'll be prompted to choose from one of three project templates:
 | `react`                | A React package with necessary development dependencies and `@types` installed. In addition, there is a [Parcel](https://parceljs.org/)-powered React playground you can use while you develop. |
 | `react-with-storybook` | Same as the basic React template, but with [React Storybook](https://storybook.js.org/) already setup as well.                                                                                  |
 
-After you select one, TSDX will create a folder with the project template in it and install all dependencies. Once that's done, you're ready-to-rock! Typescript, Rollup, Jest, ESlint and all other plumbing is already setup with best practices. Just start editing `src/index.ts` (or `src/index.tsx` if you chose one of the React templates) and go!
+After you select one, TSDX will create a folder with the project template in it and install all dependencies. Once that's done, you're ready-to-rock! TypeScript, Rollup, Jest, ESlint and all other plumbing is already setup with best practices. Just start editing `src/index.ts` (or `src/index.tsx` if you chose one of the React templates) and go!
 
 ## Useful Commands