chore(canvas): fix errors and miscellaneous things (discordjs#1227)

* chore(canvas): Fix errors and miscellaneous things
* chore: Always error on trailing spaces

.eslintrc.js

@@ -5,5 +5,6 @@ module.exports = {
 	rules: {
 		indent: ['error', 'tab'],
 		semi: ['error', 'always'],
+		'no-trailing-spaces': 'error',
 	},
 };

guide/popular-topics/canvas.md

@@ -142,14 +142,14 @@ const { request } = require('undici');
 client.on('interactionCreate', async interaction => {
 	// ...
 	context.strokeRect(0, 0, canvas.width, canvas.height);
-	
-	// using undici to make http requests for better performance
+
+	// Using undici to make HTTP requests for better performance
 	const { body } = await request(interaction.user.displayAvatarURL({ extension: 'jpg' }));
 	const avatar = await Canvas.loadImage(await body.arrayBuffer());
-	
-	// if you don't care about the performance of http requests, you can instead load the avatar using
+
+	// If you don't care about the performance of HTTP requests, you can instead load the avatar using
 	// const avatar = await Canvas.loadImage(interaction.user.displayAvatarURL({ extension: 'jpg' }));
-	
+
 	// Draw a shape onto the main canvas
 	context.drawImage(avatar, 25, 0, 200, canvas.height);
 	// ...