Fix some spelling errors (#5)

routes/about.js

@@ -1,7 +1,7 @@
 const express = require('express')
 const router = express.Router()
 
-/* GET home page. */
+/* GET about page. */
 router.get('/', function (req, res, next) {
   res.render('about', { title: 'About' })
 })

routes/categories.js

@@ -1,7 +1,7 @@
 const express = require('express')
 const router = express.Router()
 
-/* GET courses listing. */
+/* GET categories listing. */
 router.get('/', function (req, res, next) {
   res.render('categories', { title: 'Categories' })
 })

routes/courses.js

@@ -17,9 +17,9 @@ router.get('/', async function (req, res, next) {
   res.render('courses', { title: `All Courses (${courses.length})`, categories, courses })
 })
 
-/* GET courses listing. */
+/* GET courses listing by category. */
 router.get('/categories/:category', async function (req, res, next) {
-  // we get all the entries with the content type `course`
+  // we get all the entries with the content type `course` filtered by a category
   let courses = []
   let categories = []
   let activeCategory = ''

routes/sitemap.js

@@ -1,7 +1,7 @@
 const express = require('express')
 const router = express.Router()
 
-/* GET seeting page. */
+/* GET sitemap page. */
 router.get('/', function (req, res, next) {
   res.render('sitemap', { title: 'Sitemap' })
 })