Fixes out kwarg in matmul when axes are appended to inputs

[ndgrigorian]

This PR corrects behavior of matmul to properly account for appending of axes to inputs where one or both arguments are vectors.

Previously, these cases would raise an error, and require an out array with axes appended by the user.

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[github-actions]

Deleted rendered PR docs from intelpython.github.com/dpctl, latest should be updated shortly. 🤞

[coveralls]

coverage: 87.952% (+0.01%) from 87.941%
when pulling 55fef8e on matmul-out-dim-fix
into d7c54e4 on master.

[github-actions]

Array API standard conformance tests for dpctl=0.17.0dev0=py310h15de555_153 ran successfully.
Passed: 839
Failed: 0
Skipped: 92

[github-actions]

Array API standard conformance tests for dpctl=0.17.0dev0=py310h15de555_153 ran successfully.
Passed: 839
Failed: 0
Skipped: 92

[oleksandr-pavlyk]

LGTM! Thank you @ndgrigorian !

[github-actions]

Array API standard conformance tests for dpctl=0.17.0dev0=py310h15de555_154 ran successfully.
Passed: 839
Failed: 0
Skipped: 92