chore: reword content of getting-started.md (#1566)
chore: reword content of getting-started.md (#1566)

* Reword content of getting-started.md 

It seems more relevant to start with IntelliJ IDEA related instructions first.

* chore: rephrase some sentences

Co-authored-by: Pavel Semyonov <9fef4c3b275d1b1cf2d37bb4fde2472935675f02@users.noreply.github.com>

hltj/kotlin-web-site-cn,JetBrains/kotlin-web-site,JetBrains/kotlin-web-site,hltj/kotlin-web-site-cn,JetBrains/kotlin-web-site,hltj/kotlin-web-site-cn,JetBrains/kotlin-web-site,JetBrains/kotlin-web-site,hltj/kotlin-web-site-cn,hltj/kotlin-web-site-cn,hltj/kotlin-web-site-cn,JetBrains/kotlin-web-site