Lines increasing and decreasing indent no longer go below zero

Normally a line matched by both patterns will be decreased by one unit compared to the non-ignored lines immediately above and below. If however the line above was not indented, the line would in theory be decreased to -1 and thus just go back to zero indent for the line following it.

Frameworks/regexp/src/indent.cc

@@ -116,7 +116,7 @@ namespace indent
 		{
 			if(type & (kIncrease | kDecrease))
 				_carry = 0;
-			if(type & kDecrease)
+			if(type & kDecrease && (!(type & kIncrease) || _level > 0))
 				_level -= _indent_size;
 
 			res = _level + _carry;