Alignment is not supported

[danielhoherd]

When rendering table columns that have alignment specified via the header separator alignment syntax, alignment is not rendered.

$ cat table-example.md
| left-aligned | center-aligned | right-aligned |
| :----------- | :------------: | ------------: |
| r1c1 | r1c2 | r1c3 |
| r2c1 | r2c2 | r2c3 |
| r3c1 | r3c2 | r3c3 |
| r4c1 | r4c2 | r4c3 |
| r5c1 | r5c2 | r5c3 |
$ glow table-example.md


    LEFT-ALIGNED │ CENTER-ALIGNED │ RIGHT-ALIGNED
  ───────────────┼────────────────┼────────────────
    r1c1         │ r1c2           │ r1c3
    r2c1         │ r2c2           │ r2c3
    r3c1         │ r3c2           │ r3c3
    r4c1         │ r4c2           │ r4c3
    r5c1         │ r5c2           │ r5c3

$ prettier table-example.md
| left-aligned | center-aligned | right-aligned |
| :----------- | :------------: | ------------: |
| r1c1         |      r1c2      |          r1c3 |
| r2c1         |      r2c2      |          r2c3 |
| r3c1         |      r3c2      |          r3c3 |
| r4c1         |      r4c2      |          r4c3 |
| r5c1         |      r5c2      |          r5c3 |