Shrink Value by boxing Range/Closure (#12784)

# Description
On 64-bit platforms the current size of `Value` is 56 bytes. The
limiting variants were `Closure` and `Range`. Boxing the two reduces the
size of Value to 48 bytes. This is the minimal size possible with our
current 16-byte `Span` and any 24-byte `Vec` container which we use in
several variants. (Note the extra full 8-bytes necessary for the
discriminant or other smaller values due to the 8-byte alignment of
`usize`)

This is leads to a size reduction of ~15% for `Value` and should overall
be beneficial as both `Range` and `Closure` are rarely used compared to
the primitive types or even our general container types.

# User-Facing Changes
Less memory used, potential runtime benefits.

(Too late in the evening to run the benchmarks myself right now)

crates/nu-cmd-lang/src/example_support.rs

@@ -223,7 +223,7 @@ impl<'a> std::fmt::Debug for DebuggableValue<'a> {
             Value::Date { val, .. } => {
                 write!(f, "Date({:?})", val)
             }
-            Value::Range { val, .. } => match val {
+            Value::Range { val, .. } => match **val {
                 Range::IntRange(range) => match range.end() {
                     Bound::Included(end) => write!(
                         f,