Report & fix colons `:` as attribute/value separators

[radeksimko]

Background

It is possible to write map/object in two different ways:

locals {
  one = {
    foo : "bar"
  }
  two = {
    foo = "bar"
  }
}

The equal sign is considered best practice separator, which is supported by that separator being used when objects/maps are rendered by Terraform CLI and also by majority of existing configuration in docs and elsewhere using this separator.

Proposal

• Report : as attribute/value separators as a informative or warning diagnostic (perhaps warning is too much given that this is purely stylistic problem which does not impact functionality)
• Provide quick fix code action which resolves the diagnostic by turning colon into equal sign