Aligned to the changes in engine

src/bold/boldediting.js

@@ -37,7 +37,7 @@ export default class BoldEditing extends Plugin {
 			upcastAlso: [
 				'b',
 				{
-					style: {
+					styles: {
 						'font-weight': 'bold'
 					}
 				}

src/code/codeediting.js

@@ -34,7 +34,7 @@ export default class CodeEditing extends Plugin {
 			model: CODE,
 			view: 'code',
 			upcastAlso: {
-				style: {
+				styles: {
 					'word-wrap': 'break-word'
 				}
 			}

src/italic/italicediting.js

@@ -36,7 +36,7 @@ export default class ItalicEditing extends Plugin {
 			upcastAlso: [
 				'em',
 				{
-					style: {
+					styles: {
 						'font-style': 'italic'
 					}
 				}

src/strikethrough/strikethroughediting.js

@@ -38,7 +38,7 @@ export default class StrikethroughEditing extends Plugin {
 				'del',
 				'strike',
 				{
-					style: {
+					styles: {
 						'text-decoration': 'line-through'
 					}
 				}

src/underline/underlineediting.js

@@ -34,7 +34,7 @@ export default class UnderlineEditing extends Plugin {
 			model: UNDERLINE,
 			view: 'u',
 			upcastAlso: {
-				style: {
+				styles: {
 					'text-decoration': 'underline'
 				}
 			}