Add Block Elements and Box Drawing to Noto Sans Symbols 2 #93

Note: this is mentioned in issue #26 but I also wanted to mention that Box Drawing should also be added.

Symbols for Legacy Computing is an extension of these 2 blocks, so they should be added to Noto Sans Symbols 2.
(Although they were included in CJK fonts, but the style doesn’t match)

Requested blocks:
Box Drawing: U+2500-U+257F
Block Elements: U+2580-U+259F

Missing characters from Legacy Computing that are in Block Elements:

U+258C LEFT HALF BLOCK ≡ BLOCK SEXTANT-135 ≡ BLOCK OCTANT-1357
U+2590 RIGHT HALF BLOCK ≡ BLOCK SEXTANT-246 ≡ BLOCK OCTANT-2468
U+2580 UPPER HALF BLOCK ≡ BLOCK OCTANT-1234
U+2584 LOWER HALF BLOCK ≡ BLOCK OCTANT-5678
U+2594 UPPER ONE EIGHT BLOCK ≡ HORIZONTAL ONE EIGHTH BLOCK-1
U+2581 LOWER ONE EIGHT BLOCK ≡ HORIZONTAL ONE EIGHTH BLOCK-8
U+258F LEFT ONE EIGHT BLOCK ≡ VERTICAL ONE EIGHTH BLOCK-1
U+2595 RIGHT ONE EIGHT BLOCK ≡ VERTICAL ONE EIGHTH BLOCK-8

(There are still more which I’m not going to list)

There are also extensive characters in Legacy Computing that are originated from Box Drawing:

U+1FBAF BOX DRAWINGS LIGHT HORIZONTAL WITH VERTICAL STROKE

(There still more which I’m not going to list)

It should be easy to make since some of them can be copied from CJK fonts or from the existing Legacy Computing block.