testing: rephrase the sentence about naming test files
This updates the explanation about
naming test files to be a little more clear.
Fixes #57389
Change-Id: I9b3a8e2dae5e3ad398b55624e183809b7d90864c
GitHub-Last-Rev:
9ff81b74b201ca032fd373424aa02a3fedaec008
GitHub-Pull-Request: golang/go#57399
Reviewed-on: https://go-review.googlesource.com/c/go/+/458435
Reviewed-by: Ian Lance Taylor <iant@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Auto-Submit: Ian Lance Taylor <iant@google.com>
Reviewed-by: Fahad King <fahadking750@gmail.com>
Reviewed-by: Rob Pike <r@golang.org>
Run-TryBot: Ian Lance Taylor <iant@google.com>
Reviewed-by: David Chase <drchase@google.com>