Update doc

Author: EugeneFlesselle

compiler/src/dotty/tools/dotc/core/Types.scala

@@ -1519,24 +1519,24 @@ object Types extends TypeUtils {
       }
       deskolemizer(this)
 
-    /** Contant fold applied compiletime ops if possible */
+    /** Constant fold applied compiletime operations if possible */
     final def compiletimeConstantFolded(using Context) = this match
       case tp: AppliedType => tp.tryCompiletimeConstantFold.orElse(this)
       case tp => tp
 
-    /** The result of normalization using `tryNormalize`, or the type itself if
-     *  tryNormlize yields NoType
-     */
+    /** The result of normalization, or the type itself if none apply. */
     final def normalized(using Context): Type = tryNormalize.orElse(this)
 
-    /** If this type can be normalized at the top-level by rewriting match types
-     *  of S[n] types, the result after applying all toplevel normalizations,
-     *  otherwise NoType
+    /** If this type has an underlying match type, the result after applying all
+     *  toplevel normalizations, otherwise NoType.
      */
     def tryNormalize(using Context): Type = underlyingMatchType match
       case mt: MatchType => mt.reduced.normalized
       case _ => NoType
 
+    /** Perform successive dealiasings and beta-reductions of applied types until
+     *  a match type is reached if any, otherwise NoType.
+     */
     def underlyingMatchType(using Context): Type = this.safeDealias.stripLazyRef match
       case tp: MatchType => tp
       case tp: AppliedType => tp.underlyingMatchType