Fix the spelling in a comment.

src/Compilers/CSharp/Portable/CSharpParseOptions.cs

@@ -42,7 +42,7 @@ public override IEnumerable<string> PreprocessorSymbolNames
             IEnumerable<string> preprocessorSymbols = null)
             : this(languageVersion.MapLatestToVersion(), documentationMode, kind, preprocessorSymbols.ToImmutableArrayOrEmpty())
         {
-            // We test the mapped value, LanguageVersion, rather than tha parameter, languageVersion,
+            // We test the mapped value, LanguageVersion, rather than the parameter, languageVersion,
             // which has not had "Latest" mapped to the latest version yet.
             if (!LanguageVersion.IsValid())
             {

src/Compilers/VisualBasic/Portable/VisualBasicParseOptions.vb

@@ -40,7 +40,7 @@ Namespace Microsoft.CodeAnalysis.VisualBasic
                         If(preprocessorSymbols Is Nothing, DefaultPreprocessorSymbols, ImmutableArray.CreateRange(preprocessorSymbols)),
                         ImmutableDictionary(Of String, String).Empty)
 
-            ' We test the mapped value, _languageVersion, rather than tha parameter, languageVersion,
+            ' We test the mapped value, _languageVersion, rather than the parameter, languageVersion,
             ' which has Not had "Latest" mapped to the latest version yet.
             If Not _languageVersion.IsValid Then
                 Throw New ArgumentOutOfRangeException(NameOf(languageVersion))