Extends color expression help to mention HEX color notation

and color name Which seems to be possible to use as well

Author: SrNetoChan

src/core/qgsproperty.cpp

@@ -86,12 +86,12 @@ QgsPropertyDefinition::QgsPropertyDefinition( const QString& name, const QString
 
     case ColorWithAlpha:
       mTypes = DataTypeString;
-      mHelpText = QObject::tr( "string [<b>r,g,b,a</b>] as int 0-255" );
+      mHelpText = QObject::tr( "string [<b>r,g,b,a</b>] as int 0-255 or #<b>RRGGBBAA</b> as hex or <b>color</b> as color's name" );
       break;
 
     case ColorNoAlpha:
       mTypes = DataTypeString;
-      mHelpText = QObject::tr( "string [<b>r,g,b</b>] as int 0-255" );
+      mHelpText = QObject::tr( "string [<b>r,g,b</b>] as int 0-255 or #<b>RRGGBB</b> as hex or <b>color</b> as color's name" );
       break;
 
     case PenJoinStyle:

src/gui/qgsdatadefinedbutton.cpp

@@ -809,12 +809,12 @@ QString QgsDataDefinedButton::unitsMmMuPercentDesc()
 
 QString QgsDataDefinedButton::colorNoAlphaDesc()
 {
-  return tr( "string [<b>r,g,b</b>] as int 0-255" );
+  return tr( "string [<b>r,g,b</b>] as int 0-255 or #<b>RRGGBB</b> as hex or <b>color</b> as color's name" );
 }
 
 QString QgsDataDefinedButton::colorAlphaDesc()
 {
-  return tr( "string [<b>r,g,b,a</b>] as int 0-255" );
+  return tr( "string [<b>r,g,b,a</b>] as int 0-255 or #<b>RRGGBBAA</b> as hex or <b>color</b> as color's name" );
 }
 
 QString QgsDataDefinedButton::textHorzAlignDesc()