* Additional Coverage for Reader Xls
More than 750 lines are newly covered, increasing overall coverage on my machine from 91.14% to 93.09%.
* Update FormulasTest.php
Reduce number of Phpstan messages by addressing their issues. Reader/Ods will require a separate ticket. Reader/Xls will require many separate tickets.
* Update PR template
* Trim trailing space
* Support for configuring a Chart Title's overlay
* Provide test coverage for getting/setting a Chart Legend's overlay
Add missing docblock
* Breaking Change to toFormattedString and 3 toArray Methods
DocBlock says `toFormattedString` returns string, but code can return int, float, bool, null, or RichText. I think the DocBlock is correct (function name clearly indicates "to string"), and the code needs to change to match it. This is not that big a deal on its own. However, some methods in `Worksheet` call this function by default - `rangeToArray`, `toArray`, and `namedRangeToArray`. All 3 can be called with a parameter so that they don't call `toFormattedString`, but, by default, they do call, and so are affected by this change. Some unit test results are changed as a result of this code change. In all those cases, an additional test is added which would match the previous result.
* Update Change Log
I often skip this till later, but, since it's a breaking change ...
* Scrutinizer, Plus Strange Cast to -0
Avoid Scrutinizer complaint by casting string to float, but ... Php decides resulted should sometimes be `-0`? That caused test failures. Very odd.
* Additional Unit Tests for XIRR and XNPV
See discussion in issue #3297. Excel result disagreed with PhpSpreadsheet, but it seems apparent that the error is Excel's. Although we have other test cases where Excel and PhpSpreadsheet disagree, those have so far been cases where Excel cannot give an answer because its algorithm does not converge, which is possible for any algorithm. In the issue in question, Excel seems to converge to a different answer; this is different than the other exceptions, and so deserves documentation with a formal test case. The discussion also mentions some cases where XNPV seems to give the wrong result in Excel, and those cases are added for XNPV.
* Scrutinizer
Whatever.
Fix#3055. Xls Reader can set vertical break specifying row 0, causing an exception. It is doubtful that Excel needs a row for a vertical break; code is changed to use row 1 if the input file specifies row 0 (or lower). Code in question has not been exercised in unit test suite. Similarly, code to set horizontal break (which probably does not have a bug) is not exercised in test suite. Finally, page order in Writer incorrectly uses value in opposite way that Reader does. A new sample is added to illustrate that these are all handled correctly; it is easier to verify this by visually comparing the source spreadsheet and the copy made from it. A unit test is also added for the same spreadsheet to formally assert that the 3 properties in question are both read and written correctly.
* Resolve Phpstan Messages in Calculation Statistical
Reduce number of Phpstan messages by addressing their issues.
I did not eliminate the messages for Trends, because I did not understand why it is working as it does, so felt it was better to leave it alone.
* Scrutinizer
A new false positive.