Add a link to documentation on OOM task failure

[kananb]

Summary of the Pull Request

Add more logging to OOM task failures, including a link to our docs on such events.

PR Checklist

• Applies to work item: #xxx
• CLA signed. If not, go over here and sign the CLI.
• Tests added/passed
• Requires documentation to be updated
• I've discussed this with core contributors already. If not checked, I'm ready to accept this work might be rejected in favor of a different grand plan. Issue number where discussion took place: #xxx

Info on Pull Request

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Validation Steps Performed

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[codecov-commenter]

Codecov Report

Merging #3602 (71d870d) into main (d50fd48) will increase coverage by 1.06%.
The diff coverage is 0.00%.

@@            Coverage Diff             @@
##             main    #3602      +/-   ##
==========================================
+ Coverage   39.95%   41.02%   +1.06%     
==========================================
  Files         303      303              
  Lines       37724    37736      +12     
  Branches     1738     1738              
==========================================
+ Hits        15073    15481     +408     
+ Misses      22330    21934     -396     
  Partials      321      321              

Files	Coverage Δ
src/agent/onefuzz-task/src/managed/cmd.rs	0.00% <0.00%> (ø)

... and 11 files with indirect coverage changes