feat(docs): add screenshot + testscript

Author: gorillamoe

README.md

@@ -82,4 +82,8 @@ This will open the current file in diff mode with the conflicts highlighted.
 The left side shows the resolution,
 the right side shows the differences between the branches.
 
+![diffconflicts screenshot](assets/screenshot.png)
+
 So all you need to do is edit the left side to resolve the conflicts.
+
+To abort the merge, simply `:cquit`.

assets/screenshot.png

@@ -0,0 +1,38 @@
+#!/usr/bin/env bash
+
+git init tmp/testrepo
+cd tmp/testrepo || exit 1
+
+cat << EOF > main.js
+console.log('Hello, world!');
+console.log('This is a test.');
+console.log('Goodbye, world!');
+EOF
+
+git add main.js
+git commit -m 'Commit One'
+
+git branch branchA
+
+cat << EOF > main.js
+console.log('Hello, everyone!');
+console.log('This is a test.');
+console.warn('Goodbye, world.');
+EOF
+
+git add main.js
+git commit -m 'Commit Two'
+
+git checkout branchA
+
+cat << EOF > main.js
+console.log('Hello, world!');
+console.log('This is a test!!!');
+console.info('Farewell, world!');
+EOF
+
+git add main.js
+git commit -m 'Commit Three'
+
+git checkout main
+git merge branchA

scripts/make-conflicts.sh

@@ -0,0 +1,2 @@
+*
+!.gitignore