Editorial: Add descriptions to abstract operations missing them

[jessealama]

Closes #2929.

Adds short description text to new Temporal abstract operations that were missing. Only new Temporal AOs were touched; some 262 and 402 AOs also show up here with empty descriptions, but I didn't touch them (they already have empty descriptions in 262/402). In many cases it's not clear to me that we have anything more to add that the description that ecmarkup would provide on its own.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 98.09%. Comparing base (978311d) to head (98bf2e2).
⚠️ Report is 2 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #3276   +/-   ##
=======================================
  Coverage   98.09%   98.09%           
=======================================
  Files          22       22           
  Lines       10457    10457           
  Branches     1808     1808           
=======================================
  Hits        10258    10258           
  Misses        182      182           
  Partials       17       17           

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[ptomato]

Thanks!