cmd/go/internal/vcs: replace [A-Za-z0-9_] with \w in regexps
cmd/go/internal/vcs: replace [A-Za-z0-9_] with \w in regexps

Change-Id: Ibcc7dbb528585b019ff1b743792a52f43a4c2233
GitHub-Last-Rev: e907fb00e3202ce394750542084569058b7d960e
GitHub-Pull-Request: golang/go#54882
Reviewed-on: https://go-review.googlesource.com/c/go/+/428535
Reviewed-by: Bryan Mills <1c8aad60184261ccede67f5c63a0d2a3bf3c9ff4@google.com>
Reviewed-by: Michael Knyszek <4473450dc5c88f06e1fb787f303d7805ec2aee65@google.com>
Run-TryBot: Bryan Mills <1c8aad60184261ccede67f5c63a0d2a3bf3c9ff4@google.com>
TryBot-Result: Gopher Robot <66cb808b70d30c07676d5e946fee83fd561249e5@golang.org>

golang/go,golang/go,golang/go,golang/go,golang/go,golang/go,golang/go,golang/go