* Display sparse matrices by showing their structure with braille patterns

* Adopt test which involves showing of sparse matrix

* Adopt docstrings

* Call `rowvals(S)` only once

* Extend code documentation

* Simplify calculation of `scaleHeight` and `scaleWidth`

* Make `brailleBlocks` a `const`

* Initialize `brailleGrid` with `UInt16(10240)`

* Let the compiler do the conversion of `\n`

* Improve printing to `io`

* Unwrap the helper functions directly into the loop

* Show small sparse matrix in traditional manner

* Add tests for `isstored`

* Adapt tests for `show`

* Adapt doctests

* Use `m` and `n` instead of `size` calls

* Initialize `scaleHeight` and `scaleWidth` in `else` clause

* Reenable commented test

* Declare type of `maxHeight` and `maxWidth`

* Do not print leading newline in `_show_with_braille_patterns`

* Reenable test for issue 30589

* Shorten type declarations of `maxHeight` and `maxWidth`

* Add `isstored` to Base

* Add `isstored` for sparse vectors

* Make use of Base function `isstored`

* Add `boundscheck` macro

* Clarify news

* Call `issorted` by `Base.issored`

* Use `Base.isstored` in tests

* Set cutoff value to print sparse matrices with braille to 16

Co-authored-by: Steven G. Johnson <stevenj@alum.mit.edu>