This is a leftover Scrutinizer change, but it needed more attention than most others. Chart/Title DocBlocks define caption as `null|string`. However, in the wild, Excel usually presents the caption as an array, and not an array of strings but rather of RichText items. I am not sure why an array is needed since a RichText item can contain many text runs, but things are what they are.
Reader/Xlsx/ChartTitleTest reads a spreadsheet with the captions stored as a RichText array. Since it performs array operations on something the DocBlock says cannot be an array, Scrutinizer objects, although not seriously enough to fail the module. Phpstan also objects; its objection is silenced with an annotation. Aside from this test, there are other tests which do set the caption to a string, and Excel seems to handle that without a problem. So, I have changed the DocBlock to specify `array|RichText|String`. I have dropped null as a possibility; nullstring will do equally well.
Because getCaption can now return multiple datatypes, I think a new function which can return the text portion of the entire caption as a single string is needed. I have added it. This simplifies the test named above, and some code in Writer/Html. The latter is not part of unit testing because the version of JpGraph found in Composer is too antiquated. I verified the Html change manually by running samples/Chart/32_Chart_read_write_HTML.php using a recent version of JpGraph. It was as a result of this test that I uncovered issue #2203. I did not see anything about Charts in docs, so did not add a description of the new function there.
Phpstan is happy with the changes. We'll see how Scrutinizer feels when I push it.
Because even if it doesn't make a difference in practice, it is
technically more correct to call static methods statically. It
also better advertise that those methods can be used from any context.
Owen Leibman
Adrien Crivelli
Krzysztof Ruszczynski
Michael Bollman
Gabriel Caruso
Zharikov Viktor