Mention vectors in more docstrings

[nalimilan]

Some functions were documented as applying only to matrices but they actually work for vectors too.

[nalimilan]

BTW I've noticed that in the manual the docstring for findnz documenting the vector method is missing, despite being listed in index.md. Any ideas?
https://docs.julialang.org/en/v1.12-dev/stdlib/SparseArrays/#SparseArrays.findnz

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 84.10%. Comparing base (4fd3aad) to head (c2e11f0).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #591      +/-   ##
==========================================
+ Coverage   84.07%   84.10%   +0.02%     
==========================================
  Files          12       12              
  Lines        9188     9189       +1     
==========================================
+ Hits         7725     7728       +3     
+ Misses       1463     1461       -2     

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[ViralBShah]

Probably just an oversight.

[nalimilan]

Thanks. Anybody willing to merge? I don't have the permissions.