Add docstring for tsdoc.

[dajiaji]

No description provided.

[codecov-commenter]

Codecov Report

Merging #273 (2cc9162) into main (ead3df4) will increase coverage by 0.04%.
Report is 6 commits behind head on main.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main     #273      +/-   ##
==========================================
+ Coverage   97.52%   97.56%   +0.04%     
==========================================
  Files          35       35              
  Lines        2225     2262      +37     
  Branches      216      216              
==========================================
+ Hits         2170     2207      +37     
  Misses         54       54              
  Partials        1        1              

Flag	Coverage Δ
unittests	97.56% <100.00%> (+0.04%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files Changed	Coverage Δ
src/cipherSuite.ts	100.00% <ø> (ø)
src/aeads/aesGcm.ts	100.00% <100.00%> (ø)
src/aeads/chacha20Poly1305.ts	100.00% <100.00%> (ø)
src/aeads/exportOnly.ts	100.00% <100.00%> (ø)
src/kdfs/hkdf.ts	98.42% <100.00%> (+0.07%)	⬆️
src/kems/dhkemX25519.ts	100.00% <100.00%> (ø)
src/kems/dhkemX448.ts	100.00% <100.00%> (ø)