Fix typos and errors in course

[Dich0tomy]

Description

Type of Change

Changes in docs (docs)

• ✨ improve(docs) - e.g. added a new paragraph, example, using a better wording, adding a new document, etc.
• 🛠️ fix(docs) - bug fix, e.g. fix a typo, page render issue
• ❌ BREAKING CHANGE(docs) - e.g. removing a document/article/category that was referenced in many other places
• 🧹 refactor(docs) - changed a code example, e.g. replaced old code with a modern one
• 🗑️ chore(docs) - other changes that don't affect the docs, e.g. updating the CI/CD pipeline

Changes in the platform (platform)

• ✨ feat(platform) - a new feature, e.g. a new MDX component, plugin, theme, etc.
• 🛠️ fix(platform) - bug fix, e.g. fix a typo, issue causing component to crash
• ❌ BREAKING CHANGE(platform) - e.g. removing a feature, changing the API, etc.
• 🧹 refactor(platform) - code improvements, changes, e.g. unifying style, renaming internals, etc.
• 📝 docs(platform) - updated code documentation
• 🗑️ chore(platform) - other changes that don't affect the platform directly, e.g. updating the CI/CD pipeline