Fix typos:
...
atribute ==> attribute
...
@end defun
@defvar Color.is_none
-This atribute is boolean. If its value is @code{True} then color is terminal's
+This attribute is boolean. If its value is @code{True} then color is terminal's
default.
@end defvar
@defvar Color.is_indexed
-This atribute is boolean. If its value is @code{True} then color is indexed,
+This attribute is boolean. If its value is @code{True} then color is indexed,
i.e. belongs to some palette.
@end defvar
@defvar Color.is_direct
-This atribute is boolean. If its value is @code{True} then this object
+This attribute is boolean. If its value is @code{True} then this object
describes direct colour in the sense of ISO/IEC 8613-6.
@end defvar