[code coverage] Clean up doc images.

R=stgao,liaoyuke
NOTRY=true

Change-Id: I4cd13877a9ce374a2b87df57a6673b09e6fdb130
Reviewed-on: https://chromium-review.googlesource.com/c/1446410
Auto-Submit: Roberto Carrillo <[email protected]>
Reviewed-by: Shuotao Gao <[email protected]>
Commit-Queue: Shuotao Gao <[email protected]>
Cr-Commit-Position: refs/heads/master@{#627562}
diff --git a/docs/code_coverage.md b/docs/code_coverage.md
index 420d247..5da26c5 100644
--- a/docs/code_coverage.md
+++ b/docs/code_coverage.md
@@ -8,8 +8,7 @@
   * [Coverage Builders](#coverage-builders)
   * [Coverage Service](#coverage-service)
   * [Coverage Clients](#coverage-clients)
-- [Coverage Script](#coverage-script)
-- [Workflow](#workflow)
+- [Local Coverage Script](#local-coverage-script)
   * [Step 0 Download Tooling](#step-0-download-tooling)
   * [Step 1 Build](#step-1-build)
   * [Step 2 Create Raw Profiles](#step-2-create-raw-profiles)
@@ -115,7 +114,7 @@
 by CQ bot. Or see this
 [15-second video tutorial](https://www.youtube.com/watch?v=cxXlYcSgIPE)
 
-## Coverage Script
+## Local Coverage Script
 The [coverage script] automates the process described below and provides a
 one-stop service to generate code coverage reports locally in just one command.