Request for more folding range kinds

Request

Currently we have just three range kinds: imports, comment and region. Even though the FoldingRange.kind is defined as string and is meant to be extensible, current situation does not lead to new kinds being agreed between clients and servers. Clients do not want to add kinds that servers do not produce, and servers don't want to add kinds that are not supported by clients.

Adding more kinds would allow servers to emit more detailed folding structure and let clients offer users greater customization options, e.g. if servers emitted method_with_docblock, docblock, method, method_body for the following code:

/**                         // <== method_with_docblock, docblock
 * @param int $param
 */                         // <== docblock end
function func($param): int  // <== method
{                           // <== method body
 ....
}                           // <== method body end, method end, method_with_docblock end 

clients/users would be able to configure folding in various ways just by toggling what kinds of folding ranges a client would recognize.

Examples

Folding method_with_docblock (the function func($param): int is assumed to be produced by providing collapsedText with the corresponding folding range

+-- function func($param): int --

Folding docblock and method_body

+-- /** --
+-- function func($param): int --
{
+--
}

Start by reviewing the existing FoldingRange.kind definition and the three current kinds named in the issue: imports, comment, and region. Done means reaching agreement on additional standardized folding kinds and reflecting that decision in the protocol specification and examples.