Bump Obs Guide chunk level

[dedemorton]

We need to bump the chunk level to accommodate the new Obs IA.

[github-actions]

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[dedemorton]

I need to cleanup some of the source files before this PR will be ready. The good news is that most of the discrepancies (when comparing file count for master with this branch) are in newer source files so we don't have to backport too far.

Rhodas-MBP:myscripts$ ./countfiles.sh
counting files in docs_bk_3045
Checking out branch....
Counting files....
Files in 8.8
     347
Files in 8.9
     358
Files in 8.10
     362
Files in 8.11
     371
Files in 8.12
     397
Files in 8.13
     573
Files in 8.14
     669
Files in 8.15
     677
Rhodas-MBP:myscripts$ ./countfiles.sh
counting files in master
Checking out branch....
Counting files....
Files in 8.8
     347
Files in 8.9
     358
Files in 8.10
     362
Files in 8.11
     371
Files in 8.12
     378
Files in 8.13
     554
Files in 8.14
     604
Files in 8.15
     612

[dedemorton]

Looks like this is ready to go. Comparison of file count across affected versions checks out.

Rhodas-MBP:myscripts$ ./countfiles.sh
Checking out master...
Already on 'master'
Your branch is up to date with 'origin/master'.
Counting files in master...
Files in 8.8
     347
Files in 8.9
     358
Files in 8.10
     362
Files in 8.11
     371
Files in 8.12
     378
Files in 8.13
     554
Files in 8.14
     604
Files in 8.15
     612
Files in master
     612
Checking out docs_bk_3045...
Updating files: 100% (2045/2045), done.
Switched to branch 'docs_bk_3045'
Your branch is up to date with 'origin/docs_bk_3045'.
Counting files in docs_bk_3045...
Files in 8.8
     347
Files in 8.9
     358
Files in 8.10
     362
Files in 8.11
     371
Files in 8.12
     378
Files in 8.13
     554
Files in 8.14
     604
Files in 8.15
     612
Files in master
     612

[bmorelli25]

looks good