Remove Old Style `..` Format

I'd like a nice way to have an old input with
```
[Mesh]
  [./a_sub_block]
    type = NewMesh
  [../]
[]
```
changed into the new format looking like
```
[Mesh]
  [a_sub_block]
    type = NewMesh
  []
[]

The highlighting has not been updated to the new format, but other things have. A second look wouldn't hurt.