DEC Spec: !error statement is not permitted in DEC file

Cc: Liming Gao <liming.gao@intel.com>
Cc: Michael Kinney <michael.d.kinney@intel.com>
Cc: Kevin W Shaw <kevin.w.shaw@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Yonghong Zhu <yonghong.zhu@intel.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>

Author: Yonghong Zhu

2_dec_file_overview/22_declaration_file_format.md

@@ -1,7 +1,7 @@
 <!--- @file
   2.2 Declaration File Format
 
-  Copyright (c) 2007-2017, Intel Corporation. All rights reserved.<BR>
+  Copyright (c) 2007-2018, Intel Corporation. All rights reserved.<BR>
 
   Redistribution and use in source (original document form) and 'compiled'
   forms (converted to PDF, epub, HTML and other formats) with or without
@@ -406,3 +406,7 @@ code and must follow the C variable name rule.
 ### 2.2.8 Conditional Directive Statements (!if...)
 
 Conditional statements are NOT permitted in EDK II DEC files.
+
+### 2.2.9 !error Statements
+
+The `!error` statement is NOT permitted in EDK II DEC files.

3_edk_ii_dec_file_format/32_package_declaration_dec_definitions.md

@@ -401,7 +401,11 @@ The conditional statements are not permitted anywhere within the DEC file.
 
 The !include statement is not permitted in an EDK II DEC file.
 
-### 3.2.5 Special Comment Blocks
+### 3.2.5 !error Statement
+
+The `!error` statement is not permitted in an EDK II DEC file.
+
+### 3.2.6 Special Comment Blocks
 
 This section defines special format comment blocks that contain information
 about this package. These command blocks are not required.

README.md

@@ -171,3 +171,5 @@ Copyright (c) 2007-2017, Intel Corporation. All rights reserved.
 | 1.27       | Update Version to 1.27                                                                                                                              | Mar 2018        |
 |            | Add flexible PCD value format into spec                                                                                                             |                 |
 |            | Add structure PCD definition syntax                                                                                                                 |                 |
+|            | Add clarification that !error statement is not permitted in DEC file                                                                                |                 |
+