Lua core - Small Changes to Intro to Lua Workout

[junoocha]

• Simplified question for insight 2
• Clarified the purpose of insight 3 to be an intro to coding in general
• Clarified the course to be Lua language focused in the last insight, and to look to the other course for Roblox related course material

[enki-hq]

Insight previews:

• [ ] enkidevs/curriculum/lua/lua-core/intro-to-functions-in-lua-iii/vararg-expression-in-lua-ii.md
• [ ] enkidevs/curriculum/lua/lua-core/intro-to-lua/intro-code-lua.md
• [ ] enkidevs/curriculum/lua/lua-core/intro-to-lua/what-to-expect.md
• [ ] enkidevs/curriculum/lua/lua-core/intro-to-lua/why-learn-lua.md