reset test name color before newline

[siadat]

I'm capturing the output of "go test" (and hence go-testdeep) and prepending a string to the output. The yellow color of the test-name line leaks to the prefix of the next line.

Before this PR (see the third line):

⚫️ [prefix with default color] --- FAIL: TestParse (0.00s)
⚫️ [prefix with default color]    some_test.go:16: Failed test
🟡 [prefix with YELLOW color]          DATA: should NOT be an error
⚫️ [prefix with default color]                      got: (*errors.errorString)(0xc00010a780)(not implemented)
⚫️ [prefix with default color]                 expected: nil
...

After this PR:

⚫️ [prefix with default color] --- FAIL: TestParse (0.00s)
⚫️ [prefix with default color]      some_test.go:16: Failed test
⚫️ [prefix with default color]         DATA: should NOT be an error
⚫️ [prefix with default color]                      got: (*errors.errorString)(0xc00010a780)(not implemented)
⚫️ [prefix with default color]                 expected: nil
...

I quite like the colors of go-testdeep (fantastic readability is one of the reason I use it), so I want to keep the colors in this case.

[coveralls]

Pull Request Test Coverage Report for Build 911530142

• 3 of 3 (100.0%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+2.0e**-05%**) to 99.837%

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Totals
Change from base Build 843296436:	2.0e-05%
Covered Lines:	8562
Relevant Lines:	8576

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💛 - Coveralls

[maxatome]

Thanks!