_content/blog: fix issues in test coverage blog post

- Fix typo in GitHub.
- Remove duplicated word.
- Code blocks must be indented with TAB to render correctly.

Change-Id: I71b6962aab1379ceaab71b8747d1457337a2111c
Reviewed-on: https://go-review.googlesource.com/c/website/+/474876
TryBot-Result: Gopher Robot <gobot@golang.org>
Auto-Submit: Ian Lance Taylor <iant@google.com>
Reviewed-by: Carlos Amedee <carlos@golang.org>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Run-TryBot: Ian Lance Taylor <iant@google.com>
diff --git a/_content/blog/integration-test-coverage.md b/_content/blog/integration-test-coverage.md
index af55859..49b9236 100644
--- a/_content/blog/integration-test-coverage.md
+++ b/_content/blog/integration-test-coverage.md
@@ -146,8 +146,8 @@
 For example, suppose we improve our test by adding these two additional lines to `integration_test.sh`:
 
 {{raw `
-./mdtool.exe +ty testdata/README.md  > /dev/null
-./mdtool.exe +ta < testdata/README.md  > /dev/null
+	./mdtool.exe +ty testdata/README.md  > /dev/null
+	./mdtool.exe +ta < testdata/README.md  > /dev/null
 `}}
 
 Running the coverage testing wrapper again:
@@ -231,7 +231,7 @@
 
 Each execution of a "-cover" built application will write out one or more data files to the directory specified in the GOCOVERDIR environment variable.
 If an integration test performs N program executions, you'll wind up with O(N) files in your output directory.
-There is typically a lot of duplicated content in the data files, so to compact the data and/or combine data sets from different integration test runs, you can can use the `go tool covdata merge` command to merge profiles together.
+There is typically a lot of duplicated content in the data files, so to compact the data and/or combine data sets from different integration test runs, you can use the `go tool covdata merge` command to merge profiles together.
 Example:
 
 ```