Merge pull request #16763 from lydia-duncan/fixLinearAlgebraTests
Add a use of the IO module to LinearAlgebra.leastSquares and a test file
[reviewed by @ben-albrecht]
Now that we have returned to respecting the privacy of use and import
statements when resolving methods, we need to add an explicit use of the IO
module in order to find string.format.
The tests that failed last night now pass with this change