feat(contented-pipeline): pipeline transform to include file

[fuxingloh]

What this PR does / why we need it:

As per title.

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[codecov]

Codecov Report

Merging #592 (416a3bb) into main (0551e1b) will decrease coverage by 4.96%.
Report is 35 commits behind head on main.
The diff coverage is 47.67%.

@@            Coverage Diff             @@
##             main     #592      +/-   ##
==========================================
- Coverage   85.00%   80.04%   -4.96%     
==========================================
  Files          10       12       +2     
  Lines         420      491      +71     
  Branches       73       88      +15     
==========================================
+ Hits          357      393      +36     
- Misses         63       98      +35     

Files Changed	Coverage Δ
...contented-pipeline-md/src/plugins/RehypeHeading.ts	93.54% <ø> (+6.45%)	⬆️
...contented-pipeline-md/src/plugins/RehypeMermaid.ts	43.75% <ø> (ø)
packages/contented-pipeline/src/Pipeline.ts	85.33% <0.00%> (ø)
...ages/contented-processor/src/ContentedProcessor.ts	86.41% <ø> (ø)
...ntented-pipeline-md/src/plugins/RemarkCodeblock.ts	16.12% <16.12%> (ø)
...s/contented-pipeline-md/src/plugins/RehypeShiki.ts	41.93% <41.93%> (ø)
...ented-pipeline-jest-md/src/JestMarkdownPipeline.ts	100.00% <100.00%> (ø)
...ages/contented-pipeline-md/src/MarkdownPipeline.ts	85.29% <100.00%> (ø)
...ages/contented-pipeline-md/src/UnifiedProcessor.ts	87.09% <100.00%> (-0.41%)	⬇️
...ented-pipeline-md/src/plugins/RemarkFrontmatter.ts	79.31% <100.00%> (+5.84%)	⬆️
... and 1 more