PreferCurlyFors: don't rewrite semicolon only

If we are not rewriting parentheses, we shouldn't remove semicolons as
they are required. Exclude the `if` guards, however, as they can come
without a newline or semicolon.

scalafmt-core/shared/src/main/scala/org/scalafmt/rewrite/PreferCurlyFors.scala

@@ -77,7 +77,12 @@ private class PreferCurlyFors(implicit val ftoks: FormatTokens)
           if !style.rewrite.preferCurlyFors.removeTrailingSemicolonsOnly ||
             ftoks.hasBreakAfterRightBeforeNonComment(ft) =>
         ft.meta.rightOwner match {
-          case _: Term.For | _: Term.ForYield => removeToken
+          case t @ (_: Term.For | _: Term.ForYield)
+              if ftoks.nextNonCommentAfter(ft).right.is[Token.KwIf] || {
+                val parenOrBrace = ftoks.nextNonComment(ftoks.getHead(t))
+                parenOrBrace.right.is[Token.LeftBrace] ||
+                session.claimedRule(parenOrBrace).exists(_.rule eq this)
+              } => removeToken
           case _ => null
         }