Rewrite primary constructor rationale in active voice

[Copilot]

Addresses style feedback on the Overview section's second paragraph, which used passive voice and complex phrasing that didn't follow documentation guidelines.

Changes:

• Converted passive constructions ("provides for generality") to active voice with "you" form
• Simplified verbose phrases ("at the expense of some tedium" → "add verbose syntax")
• Applied conversational tone with present tense throughout

Before:

The ability of a class or struct in C# to have more than one constructor provides for 
generality, but at the expense of some tedium in the declaration syntax, because the 
constructor input and the class state need to be cleanly separated.

After:

When you create a class or struct with multiple constructors, you gain flexibility, 
but you also add verbose syntax. You must cleanly separate the constructor input from 
the class state.

---

✨ Let Copilot coding agent set things up for you — coding agent works faster and does higher quality work when set up for your repo.

---

Internal previews

📄 File	🔗 Preview link
docs/fundamentals/code-analysis/style-rules/ide0290.md	docs/fundamentals/code-analysis/style-rules/ide0290