Backports to release-1.12

[dkarrasch]

• fix 3-argument dot #715
• Assorted optimizations for sparse dense matrix multiplication #666

[codecov]

Codecov Report

❌ Patch coverage is 95.72650% with 5 lines in your changes missing coverage. Please review.
✅ Project coverage is 84.45%. Comparing base (44d077d) to head (dfefa67).

Files with missing lines	Patch %	Lines
src/linalg.jl	95.32%	5 Missing ⚠️

Additional details and impacted files

@@               Coverage Diff                @@
##           release-1.12     #718      +/-   ##
================================================
+ Coverage         84.42%   84.45%   +0.03%     
================================================
  Files                13       13              
  Lines              9179     9233      +54     
================================================
+ Hits               7749     7798      +49     
- Misses             1430     1435       +5     

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