Fix link in autotest documentation

The link produced by the relative path is
https://chromium.googlesource.com/chromiumos/third_party/autotest/+/refs/heads/master/docs/docs/coding-style.md
where doc is duplicated.  Remove doc to fix the link.

TEST=Opened locally
BUG=None

Change-Id: I10bb6435cbdf7aebd3e3339df74903cb235b1de6
Reviewed-on: https://chromium-review.googlesource.com/453412
Commit-Ready: Sean Kau <[email protected]>
Tested-by: Sean Kau <[email protected]>
Reviewed-by: Dan Shi <[email protected]>
diff --git a/docs/best-practices.md b/docs/best-practices.md
index f4cb076..0bfc5c2 100644
--- a/docs/best-practices.md
+++ b/docs/best-practices.md
@@ -15,7 +15,7 @@
 
 ## Coding style
 
-Basically PEP-8.  See [docs/coding-style.md](docs/coding-style.md)
+Basically PEP-8.  See [docs/coding-style.md](coding-style.md)
 
 ## Where should my code live?