fix(lint): format error message with appropriate line breaks

[sudo-suhas]

Before

$ meteor lint recipe.yaml
recipe error: urn scope is required to generate unique urnsample: invalid http sink config: Key: 'Config.method' Error:Field validation for 'method' failed on the 'required' tag
sample: invalid labels processor config: Key: 'Config.labels' Error:Field validation for 'labels' failed on the 'required' tag

Some checks were not successful
1 failing, 0 successful, and 1 total

✘  sample	(3 errors, 0 warnings)

After

$ meteor lint recipe.yaml
recipe error: urn scope is required to generate unique urn
sample: invalid http sink config: Key: 'Config.method' Error:Field validation for 'method' failed on the 'required' tag

Some checks were not successful
1 failing, 0 successful, and 1 total

✘  sample	(2 errors, 0 warnings)