Prettier Landing Page

- Replaced logo with an self-created image based on the Apple symbol design for frameworks.
- Removed the "V 2" in the top level heading because it contradicts the current major version 5.
- Corrected alt text of image which appears to be copied and pasted from Nextcloud iOS app README.
- Improved orthography on testing headings.
- Added syntax definitions to some code fences.
- Minor formatting improvements.

README.md

@@ -2,18 +2,18 @@
   - SPDX-FileCopyrightText: 2022 Nextcloud GmbH and Nextcloud contributors
   - SPDX-License-Identifier: GPL-3.0-or-later
 -->
-# NextcloudKit V 2
-<img src="image.png" alt="Demo of the Nextcloud iOS files app" width="200" height="200">
 
-[![REUSE status](https://api.reuse.software/badge/github.com/nextcloud/NextcloudKit)](https://api.reuse.software/info/github.com/nextcloud/NextcloudKit)
+<div align="center">
+    <img src="NextcloudKit.png" alt="Logo of NextcloudKit" width="256" height="256" />
+    <h1>NextcloudKit</h1>
+    <img src="https://api.reuse.software/badge/github.com/nextcloud/NextcloudKit" alt="REUSE status" />
+</div>
 
 ## Installation
 
 ### Carthage
 
-[Carthage](https://github.com/Carthage/Carthage) is a decentralized dependency manager that builds your dependencies and provides you with binary frameworks.
-
-To integrate **NextcloudKit** into your Xcode project using Carthage, specify it in your `Cartfile`:
+[Carthage](https://github.com/Carthage/Carthage) is a decentralized dependency manager that builds your dependencies and provides you with binary frameworks. To integrate **NextcloudKit** into your Xcode project using Carthage, specify it in your `Cartfile`:
 
 ```
 github "nextcloud/NextcloudKit" "main"
@@ -23,9 +23,7 @@ Run `carthage update` to build the framework and drag the built `NextcloudKit.fr
 
 ### Swift Package Manager
 
-[Swift Package Manager](https://swift.org/package-manager/) is a tool for automating the distribution of Swift code and is integrated into the `swift` compiler. 
-
-Once you have your Swift package set up, adding NextcloudKit as a dependency is as easy as adding it to the `dependencies` value of your `Package.swift`.
+[Swift Package Manager](https://swift.org/package-manager/) is a tool for automating the distribution of Swift code and is integrated into the `swift` compiler. Once you have your Swift package set up, adding NextcloudKit as a dependency is as easy as adding it to the `dependencies` value of your `Package.swift`.
 
 ```swift
 dependencies: [
@@ -40,24 +38,26 @@ Then, add `NextcloudKit.xcodeproj` to your project, select your app target and a
 
 ## Testing
 
-### Unit tests:
+### Unit Tests
 
 Since most functions in NextcloudKit involve a server call, you can mock the Alamofire session request. For that we use [Mocker](https://github.com/WeTransfer/Mocker).
 
-### Integration tests:
+### Integration Tests
+
 To run integration tests, we need a docker instance of a Nextcloud test server.
 The CI does all this automatically, but to do it manually:
+
 1. Run `docker run --rm -d -p 8080:80 ghcr.io/juliushaertl/nextcloud-dev-php80:latest` to spin up a docker container of the Nextcloud test server.
 2. Log in on the test server and generate an app password for device. There are a couple test accounts, but `admin` as username and password works best.
 3. Run `./generate-env-vars.sh`. This will generate an `.env-vars` file in the root directory. It contains env vars that the project will use for testing.
 4. Provide proper values for the env vars inside the file. Here is an example:
-```
-export TEST_SERVER_URL=http://localhost:8080
-export TEST_USER=nextcloud
-export TEST_PASSWORD=FAeSR-6Jk7s-DzLny-CCQHL-f49BP
+```sh
+export TEST_SERVER_URL="http://localhost:8080"
+export TEST_USER="nextcloud"
+export TEST_PASSWORD="FAeSR-6Jk7s-DzLny-CCQHL-f49BP"
 ```
 5. Run `./generate-env-vars.sh` again to regenerate the env vars. If all the values are set correctly you will see a generated file called `EnvVars.generated.swift`. It contains the env vars as Swift fields that can be easily used in code:
-```
+```swift
 /**
 This is generated from the .env-vars file in the root directory. If there is an environment variable here that is needed and not filled, please look into this file.
  */