* Clean Up Documentation for Worksheet
This PR was intended to clean up Phpstan/Scrutinizer messages regarding Worksheet. It is, for the most part, straightforward, but there is one problem which complicates things. The frequently-called public method `getParent` returns `Worksheet` or `null` but is documented to return only `Worksheet`. This can be addressed in either of two ways - change the code to match the documentation (smaller number of changes but a backwards compatibility break), or change the documentation to match the code (larger number of changes but no compatibility break). I have prepared a PR for each approach, but avoiding a compatibility break seems better, so I am pushing the latter. I can switch to the other if preferred. Most existing internal calls to `getParent` are changed to use a new method `getParentOrThrow`, which will throw an exception if parent is null. These calls would all have thrown a null pointer exception anyhow in that situation, so this should not cause any new breaks.
* Scrutinizer
One false positive, and one message leading to a minor code improvement.
* Fix Unintential Deprecated Calls in Tests - INFORMATION
I think it's best to install these before PR #3166. There are no changes to source code, only to doc-blocks and to test members which continue to inadvertently use calls to deprecated functions.
* Missed Some Deprecated Calls
Fix them now.
Implement Array-enabled for ERROR.TYPE() function
Extract ERROR.TYPE() function tests into separate test file
Extract error function tests into separate test files
And thus complete the implemented Information functions
* First steps toward array-enabling the information functions
Also includes moving unit tests out from Functions and into a separate, dedicated Information folder
* Resolve issue with IF(), branch pruning and calculation cache (ensure that we don't convert the if condition to a bool before we've tested to see if it evaluates to an error)
More refactoring
oleibman
Mark Baker