Overhaul content of language-features.md, since I already pushed on…

…e commit for it in this PR.

See #6455 (comment) and ping @davisagli

docs/source/contributing/language-features.md

@@ -1,70 +1,64 @@
 ---
 myst:
   html_meta:
-    "description": "Volto is developed using Babel to transpile modern JavaScript to JavaScript that browsers are able to understand and execute."
-    "property=og:description": "Volto is developed using Babel to transpile modern JavaScript to JavaScript that browsers are able to understand and execute."
-    "property=og:title": "Language features and conventions"
-    "keywords": "Volto, Plone, frontend, React, Babel, translations, language, internationalization, i18n, localization, transpilation"
+    "description": "Volto uses several tools and follows conventions that provide features and browser support for the JavaScript language."
+    "property=og:description": "Volto uses several tools and follows conventions that provide features and browser support for the JavaScript language."
+    "property=og:title": "JavaScript language features and browser support"
+    "keywords": "Volto, Plone, frontend, React, Babel, JavaScript, transpilation"
 ---
+% Mixture of conceptual guide and how-to guide
+# JavaScript language features and browser support
 
-# Language features and conventions
+Volto uses several tools and follows conventions that provide features and browser support for the JavaScript language.
 
+
+% Conceptual guide
 ## Babel
 
-Volto is developed using Babel to transpile modern JavaScript to JavaScript that
-browsers are able to understand and execute.
+Babel transpiles {term}`ECMAScript` code, including React and JSX, into a backwards compatible version of JavaScript in current and older browsers or environments.
 
-Ecma International's TC39 (https://tc39.es/) is a group of JavaScript developers,
-implementers, academics, and more, collaborating with the community to maintain and
-evolve the definition of JavaScript. They stablished a process
-(https://tc39.es/process-document/) where the proposals are discussed, developed, and
-eventually approved (or dropped). The process has five stages (0 to 4) where reaching
-the stage 4 means the proposal is accepted and it becomes part of the JavaScript
-specification.
+Babel provides features and syntax that you can use in code when you develop on Volto.
+These features derive from the proposals that the {term}`TC39` produces.
 
-Babel enables a series of features and syntax that the developer can use in code to
-develop Volto on. These features are the proposals the TC39 is working on in the
-different stages of evolution.
+Volto uses `babel-razzle-preset`, which in turns uses `@babel/preset-env`, which together enable the use of all [TC39 finished proposals](https://github.com/tc39/proposals/blob/HEAD/finished-proposals.md#finished-proposals).
 
-Volto uses `babel-razzle-preset` which in turns uses `@babel/preset-env` which enables
-the use of all TC39 proposals currently in TC39's stage 4
-(https://github.com/tc39/proposals/blob/HEAD/finished-proposals.md#finished-proposals).
 
-### Browser compatibility
+% How-to guide
+## Browser compatibility
 
-Babel preset-env uses `browserlist` which gives the ability to micromanage the
-transformations needed by the current project depending of the browser support you are
-currently targeting.
+`@babel/preset-env` uses `browserslist`, which you can use to manage the transformations needed to target specific browser support in your project.
+This reduces the size of bundles, as Babel will apply only the required transforms that your target environment needs.
 
-By doing this, it enables the bundles to be smaller, as the resulting code does not need to
-support old browsers (thus, transform your code to ES5 compatible code) as Babel will
-apply only the required transforms that your target environments need. For more
-information: https://babeljs.io/docs/babel-preset-env#browserslist-integration
+```{seealso}
+https://babeljs.io/docs/babel-preset-env#browserslist-integration
+```
 
-Volto project generators use this browserlist by default (you can find it in your local `package.json`):
+Volto project generators use `browserslist` queries by default, which is in your local {file}`package.json`.
+You can adjust this file according to the environments you want to target.
 
 ```json
-  "browserslist": [
-    ">1%",
-    "last 4 versions",
-    "Firefox ESR",
-    "not ie 11",
-    "not dead"
-  ],
+"browserslist": [
+  ">1%",
+  "last 4 versions",
+  "Firefox ESR",
+  "not ie 11",
+  "not dead"
+],
+```
+
+```{seealso}
+For usage and syntax, see the `browserslist` documentation of [Queries](https://github.com/browserslist/browserslist#queries).
 ```
 
-which you can adjust depending on the environments you are targeting in your local
-`package.json` file. You can find more information about how the queries in `broserlist`
-works in: https://github.com/browserslist/browserslist#queries
 
-### Support of deprecated browsers
+% How-to guide
+## Support of deprecated browsers
 
 ```{warning}
 Volto does not support deprecated browsers, such as Internet Explorer 11.
 ```
 
-If you still need to support deprecated browsers, you should use `browserslist` in your project to enable the required transforms for the target deprecated environments you have to support.
+If you still need to support deprecated browsers, you should use `browserslist` in your project to enable the required transforms for the target deprecated environments you must support.
 
-However, Volto (or its dependencies) might not be compatible with old browsers.
-You might need to create some workarounds to make the build work, and the
-deprecated browser not crash.
+However, Volto or its dependencies might not be compatible with old browsers.
+You might need to create some workarounds to make the build work, and the deprecated browser not crash.