Add .d and .vala as filetypes

[pocc]

Both D and vala are languagse and have .vala and .d filetypes respectively. They are text files.

[asottile]

please send a PR with references -- thanks!

[ngie-eign]

@asottile : this issue is still referenced in https://github.com/pocc/pre-commit-hooks/blob/336fdd7c3cab698ead0b1c95157b9e74d3906b62/.pre-commit-hooks.yaml#L28 and I didn't see a linked PR or commit, so I opened #549 to address the ask by @pocc .