Formatting fixes.

Changing sock->type is done by node_socket_set_typeinfo.

Merge branch 'master' into temp-D10912-change-group-socket-types

Nicer labels for integer and color sockets.

Remove the ICON_PLUGIN from node socket RNA.

Removed the colored circle next to type button.

Put back socket type enums that were removed.

Reliable filtering of non-standard socket types.

Socket polling callback for trees needs to be able to distinguish
"standard" and custom sockets. Custom sockets have a type 0 by default
so that cannot be used to check the socket type. Instead use RNA to
check if a type is a standard socket type.

Remove the valid_socket_type_full method.
The valid_socket_type callback was added very recently, so there is no
harm in changing it at this point. That avoids the complication of
having two variants in the API.

See 47aca2b4c402ec35ea52c18afcc0840bcf283b26

Merge branch 'master' into D10912-change-group-socket-types

Added function for consistent socket type label.

Also register the type label for node sockets.

Align the socket type UI with the property split.

Check context pointer to avoid crashes.

Context can be NULL, e.g. when building docs or
when searching the bpy API.

Optional labels for nicer socket type names in UI.

Remove accidentally committed test script.

Changed socket validation to work on full types.

The socket validation function in `bNodeTreeType` now works on the
`bNodeSocketType` rather than just the (legacy) integer base type.
This allows custom node trees (python nodes) to check for their own
socket types, which could not otherwise be distinguished (all custom
socket types map to the SOCK_CUSTOM base type).

The registerable RNA method `valid_socket_type` of node trees remains
unchanged to avoid breaking the API. There is now an alternative
`valid_socket_type_full` method which takes the idname instead of the
old integer enum. If `valid_socket_type_full` is defined then
`valid_socket_type` is ignored.

The socket_change_type operator now uses idnames as well, filtering out
all types that are unsupported by the tree as well as subtype
specializations.

New function for changing socket type by idname.

The static integer type is only a subset of all socket types available.
To support changing to a custom socket type the nodeModifySocketType
function now takes the idname instead, while nodeModifySocketTypeStatic
implements the old behavior with integer type where it is still needed.

Type change in the group socket update function.

In group node and group input/output updates:
Instead of discarding group sockts with a type mismatch (which breaks
any link), keep the socket and update its type.
This can require a subsequent node tree link update to check for invalid
socket connections. Links should be flagged as invalid and ignored by
node systems, rather than removed outright.

Note that the nodeModifySocketType function only works with static
socket types currently and does not fully support custom socket types
(e.g. sockets defined in python). Any group interface with a custom type
will generate a generic SOCK_CUSTOM socket. This should be addressed
soon by making nodeModifySocketType work with idnames rather than
integer types.

Operator for changing the socket type in groups.