fix typos

[spaette]

docs/src/assets/dark.scss docs/src/assets/light.scss docs/src/transforms.md src/transforms/coalesce.jl src/transforms/select.jl test/transforms/levels.jl test/transforms/replace.jl

same docs style with typos as fixed in GeoStats #272, #274, and in Meshes #468

[juliohm]

Tests are failing for unrelated reasons. Merging it. Thanks!

[spaette]

the sole code change being the below

src/transforms/coalesce.jl

- colapply(tramsform::Coalesce, x, c) = coalesce.(x, tramsform.value)
+ colapply(transform::Coalesce, x, c) = coalesce.(x, transform.value)