Fix typos in MetadataBuilder (dotnet#8670)

Author: MSDN-WhiteKnight

xml/System.Reflection.Metadata.Ecma335/MetadataBuilder.xml

@@ -721,7 +721,7 @@ Entries must be added in the same order as the corresponding field definitions.
 
 ## Remarks
 
-Entires must be added in the same order as the corresponding field definitions.
+Entries must be added in the same order as the corresponding field definitions.
 
 The final relative virtual address stored in the metadata is calculated when the metadata is serialized by adding the offset to the virtual address of the block start.
           ]]></format>
@@ -1799,7 +1799,7 @@ Entries should be added in the same order as the corresponding `MoveNext` method
 
 ## Remarks
 
-Entires must be added in the same order as the corresponding type definitions.
+Entries must be added in the same order as the corresponding type definitions.
 
           ]]></format>
         </remarks>