layers: Add error codes for parameter_validation

Add error codes to the parameter_validation layer:
- Add parameter_validation::ErrorCode enum defining common parameter
  validation errors to parameter_validation_utils.h
- Replace the '1' in parameter_validation log_msg calls with the
  appropriate error code
- Add parameter_validation error code documentation to
  vk_validation_layer_details.md
- Remove 'typedef enum' declaration requirement for error code
  enumerations from vk_layer_documentation_generate.py; It will
  now recognize error code enmerations declared wihtout the typedef

Change-Id: Icf18b9124000159f7436f66e48a95d0c58047a07
diff --git a/vk_layer_documentation_generate.py b/vk_layer_documentation_generate.py
index 5e79369..4f23cd6 100755
--- a/vk_layer_documentation_generate.py
+++ b/vk_layer_documentation_generate.py
@@ -81,6 +81,10 @@
                             'source' : 'layers/swapchain.cpp',
                             'generated' : False,
                             'error_enum' : 'SWAPCHAIN_ERROR',},
+                 'parameter_validation' : {'header' : 'layers/parameter_validation_utils.h',
+                                           'source' : 'layers/parameter_validation.cpp',
+                                           'generated' : False,
+                                           'error_enum' : 'ErrorCode',},
     }
 
 builtin_headers = [layer_inputs[ln]['header'] for ln in layer_inputs]
@@ -198,8 +202,8 @@
                             if enum_name in self.layer_dict[layer_name]['CHECKS']:
                                 print('ERROR : % layer has duplicate error enum: %s' % (layer_name, enum_name))
                             self.layer_dict[layer_name]['CHECKS'].append(enum_name)
-                    # If the line includes 'typedef', 'enum', and the expected enum name, start capturing enums
-                    if False not in [ex in line for ex in ['typedef', 'enum', layer_inputs[layer_name]['error_enum']]]:
+                    # If the line includes 'enum' and the expected enum name, start capturing enums
+                    if False not in [ex in line for ex in ['enum', layer_inputs[layer_name]['error_enum']]]:
                         store_enum = True
 
         # For each source file, parse into dicts