Apply suggestions from code review

Author: hamzaremmal

compiler/src/dotty/tools/dotc/parsing/Parsers.scala

@@ -3133,8 +3133,8 @@ object Parsers {
       buf.toList
     }
 
-    /** CaseClause        ::= ‘case’ Pattern [Guard] (‘with’ SimpleExpr SubMatchClause | `=>' Block)
-     *  ExprCaseClause    ::= ‘case’ Pattern [Guard] (‘with’ SimpleExpr SubMatchClause | `=>' Expr)
+    /** CaseClause        ::= ‘case’ Pattern [Guard] (‘if’ InfixExpr MatchClause | `=>' Block)
+     *  ExprCaseClause    ::= ‘case’ Pattern [Guard] (‘if’ InfixExpr MatchClause | `=>' Expr)
      */
     def caseClause(exprOnly: Boolean = false): CaseDef = atSpan(in.offset) {
       val (pat, grd) = inSepRegion(InCase) {

compiler/src/dotty/tools/dotc/printing/RefinedPrinter.scala

@@ -566,7 +566,7 @@ class RefinedPrinter(_ctx: Context) extends PlainPrinter(_ctx) {
         }
       case CaseDef(pat, guard, body) =>
         val bodyText = body match
-          case t: SubMatch => keywordStr(" with ") ~ toText(t)
+          case t: SubMatch => keywordStr(" if ") ~ toText(t)
           case t => " => " ~ caseBlockText(t)
         keywordStr("case ") ~ inPattern(toText(pat)) ~ optText(guard)(keywordStr(" if ") ~ _) ~ bodyText
       case Labeled(bind, expr) =>