Suggest type definition install command using yarn when applicable

[astorije]

TypeScript Version: 2.8.1

Search Terms: yarn, Could not find a declaration, if it exists

Apologies if this was discussed before, I looked through issues and PRs, could not find anything.

When a yarn.lock file is present in the project directory, instead of recommending:

TS7016: Could not find a declaration file for module 'node-pkg'. '/[...]/node_modules/node-pkg/[...]' implicitly has an 'any' type.
Try `npm install @types/node-pkg` if it exists or add a new declaration (.d.ts) file containing `declare module 'node-pkg';`

it would be nice if the suggested command could make use of yarn add instead:

TS7016: Could not find a declaration file for module 'node-pkg'. '/[...]/node_modules/node-pkg/[...]' implicitly has an 'any' type.
Try `yarn add @types/node-pkg` if it exists or add a new declaration (.d.ts) file containing `declare module 'node-pkg';`

[mhegazy]

Related to #19997

[RyanCavanaugh]

This doesn't seem to be bothering anyone