Implements #9203. Pin the header of table, to make it always visible even if there are a lot of rows

Fixes #7682. 'Input textarea auto height' - Improve detection single/multiple lines, improve doc, enhance unit tests.

Fixes #1201. FE.parameter option has never been implemented. According https://developer.mozilla.org/en-US/docs/Web/HTML/Global_attributes/tabindex only the values '0' and '-1' are good. 'tabindex' has been removed from Manual.rst. FormEditor.sql has been changed that all links are 'tabindex="-1"'.

License.rst: add Twig, PhpSpreadsheet