Docs: fix some markdown links

No change to logic, only docs.

One link incorrectly line-wrapped: this fixes that. This also linkifies
another reference to a Java class, to point to the Java class in the
tree. This class seems unlikely to move, but the worst case is that the
link will be broken (and readers could probably figure this out and
search in codesearch).

R=agrieve@chromium.org

Bug: 918221
Test: Upload to gerrit > open file > click "gitiles"
Change-Id: I3d948e5fd86302e8680a4837367f8799e37dfb30
Reviewed-on: https://chromium-review.googlesource.com/c/1451536
Reviewed-by: Andrew Grieve <agrieve@chromium.org>
Auto-Submit: Nate Fischer <ntfschr@chromium.org>
Commit-Queue: Nate Fischer <ntfschr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#628994}

docs/android_logging.md

@@ -5,12 +5,13 @@
 
 ## Overview
 
-Logging used to be done using Android's [android.util.Log]
-(https://developer.android.com/reference/android/util/Log.html).
+Logging used to be done using Android's
+[android.util.Log](https://developer.android.com/reference/android/util/Log.html).
 
-A wrapper on that is now available: org.chromium.base.Log. It is designed to
-write logs as belonging to logical groups going beyond single classes, and to
-make it easy to switch logging on or off for individual groups.
+A wrapper on that is now available:
+[org.chromium.base.Log](/base/android/java/src/org/chromium/base/Log.java). It
+is designed to write logs as belonging to logical groups going beyond single
+classes, and to make it easy to switch logging on or off for individual groups.
 
 Usage: