wip(shared): Started working on jargon overhaul

See #6017

markdown/dev/reference/terms/cjs/en.md

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+---
+title: cjs
+---
+
+**cjs** stands for **CommonJS**. It is a module system for JavaScript that was
+popularized by NodeJS, and as such typically used in server-side JavaScript.
+
+CommonJS uses the **require** keyword to import modules:
+
+```js
+const fs = require('fs')
+```
+
+In recent years, **cjs** is increasingly being replaced by **esm**, or ECMA
+Script Modules which is the official module system of the JavaScript language,
+and the future-proof choice.
+
+Since version 3, FreeSewing is ESM-only.

markdown/dev/reference/terms/en.md

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+---
+title: Terminology
+---
+
+These are terms that we use on this website that may or may not be new to you:
+
+<ReadMore />

markdown/dev/reference/terms/esm/en.md

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+---
+title: esm
+---
+
+**esm** stands for **ECMAScript Modules** and is the official module system of
+the JavaScript language, supported both in the browser, and on the server.
+
+While ESM is the official standard, before it existed people would typically use CJS outside the browser, as it was popularized by NodeJS.
+Some libraries still are not available in ESM, but FreeSewing has been ESM-only since version 3.
+
+
+ESM uses the **import** keyword to import modules:
+
+```js
+import fs from 'fs'
+```
+

markdown/dev/reference/terms/variadic/en.md

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+---
+title: Variadic
+---
+
+A **variadic** function is a function that accepts a variable number of arguments.
+
+For example, JavaScript's `console.log` method is variadic:
+
+```js
+console.log('one')
+console.log('one', 'two')
+console.log('one', 'two', 'three')
+console.log('It', 'word', 'regardless', 'of', 'how', 'many', 'arguments', 'you', 'pass')
+```