Make top-level document-reference title generic

[GaryGapinski]

Accommodates #513.

This is a trivial change to the transform. However, there is no obvious transformation of the SSP, SAP, SAR, and POA&M Schematron files into JSON to be seen in the repository so I'm uncertain all that is needed is the change to the transform.

Transforms of the .sch documents are in the attached archive json.zip.

[github-actions[bot]]

XSpec Test Results

    5 files  ±0    26 suites  ±0   0s :stopwatch: ±0s 751 tests ±0  704 :heavy_check_mark: ±0  47 :zzz: ±0  0 :x: ±0  772 runs  ±0  723 :heavy_check_mark: ±0  49 :zzz: ±0  0 :x: ±0 

Results for commit c8d80e36. ± Comparison against base commit 68fef39a.

[github-actions[bot]]

XSpec Test Results

    5 files  ±0    26 suites  ±0   0s :stopwatch: ±0s 751 tests ±0  704 :heavy_check_mark: ±0  47 :zzz: ±0  0 :x: ±0  772 runs  ±0  723 :heavy_check_mark: ±0  49 :zzz: ±0  0 :x: ±0 

Results for commit 33aeca50. ± Comparison against base commit 33aeca50.