Rewrites sentence on sigilless variable

Thanks to @jimav for the suggestion. Also rewrites some other things
here and there. Refs #1784.

Author: JJ

doc/Language/containers.pod6

@@ -149,7 +149,8 @@ You've seen this situation before: it is exactly what happened with the
 signature parameter marked as C<is rw>.
 
 X<|\ (container binding)>
-Sigilless variables bind by default and so do parameters with the trait C<is raw>.
+Sigilless variables and parameters with the trait C<is raw> always
+bind (whether C<=> or C<:=> is used): 
 
     my $a = 42;
     my \b = $a;
@@ -163,8 +164,8 @@ Sigilless variables bind by default and so do parameters with the trait C<is raw
 =head1 Scalar containers and listy things
 
 There are a number of positional container types with slightly different
-semantics in Perl 6. The most basic one is L<List|/type/List>
-It is created by the comma operator.
+semantics in Perl 6. The most basic one is L<List|/type/List>; 
+it is created by the comma operator.
 
     say (1, 2, 3).^name;    # OUTPUT: «List␤»
 
@@ -182,7 +183,7 @@ you can still assign to it:
 So the list doesn't care about whether its elements are values or
 containers, they just store and retrieve whatever was given to them.
 
-Lists can also be lazy, so elements at the end are generated on demand from an
+Lists can also be lazy; in that case, elements at the end are generated on demand from an
 iterator.
 
 An C<Array> is just like a list, except that it forces all its elements to
@@ -198,7 +199,7 @@ container with the new one, C<42>.
 
 =head1 Assigning and binding to array variables
 
-Assigning to a scalar variable and to an array variable both do basically
+Assignment to a scalar variable and to an array variable both do
 the same thing: discard the old value(s), and enter some new value(s).
 
 Nevertheless, it's easy to observe how different they are:
@@ -227,8 +228,8 @@ As a curious side note, Perl 6 supports binding to array elements:
 If you've read and understood the previous explanations, it is now time to
 wonder how this can possibly work. After all, binding to a variable requires
 a lexpad entry for that variable, and while there is one for an array, there
-aren't lexpad entries for each array element (you cannot expand the lexpad
-at run time).
+aren't lexpad entries for each array element, because you cannot expand the lexpad
+at run time.
 
 The answer is that binding to array elements is recognized at the syntax
 level and instead of emitting code for a normal binding operation, a special