Fix whitespace in imports - #6421

FYI, we could add "object-curly-spacing": ["error", "always"], to catch the other cases of this (see https://eslint.org/docs/rules/object-curly-spacing and https://github.com/microsoft/vscode-cpptools/blob/master/Extension/.eslintrc.js). However, that generates a bunch of other linter errors for other cases where we don't have consistent spacing.