`sh:order` should be a number

[VladimirAlexiev]

(this bug is inspired from @YoucTagh's review of #471)

https://raw.githack.com/w3c/data-shapes/master/shacl12-core/index.html#order

The values of sh:order are decimals

• But most people use integers: 1, 2 etc and don't even know that eg 1.0, 1.5, 2.0 is valid.
• IMHO all engines would work with any numbers here, eg 1, 1.5. 2
  @bergos , @HolgerKnublauch please weigh in

Also, the Order section doesn't mention what the next section does:

Groups may also have an sh:order property to indicate the relative ordering of groups within the same form.

I think no change is needed here

[HolgerKnublauch]

Weird, I thought we had already addressed this. For example the TTL file contains

# range: xsd:decimal or xsd:integer ;

and I believe those two options are sensible. I wouldn't want to support any other numeric types there.

[TallTed]

the TTL file contains

range: xsd:decimal or xsd:integer ;

That's not Turtle.

[VladimirAlexiev]

@TallTed It is. In a comment:
https://www.w3.org/ns/shacl.ttl

sh:order
	a rdf:Property ;
	rdfs:label "order"@en ;
	rdfs:comment "Specifies the relative order of this compared to its siblings. For example use 0 for the first, 1 for the second."@en ;
	# range: xsd:decimal or xsd:integer ;
	rdfs:isDefinedBy sh: .

[TallTed]

I see. Far better if it were to be expressed (even within a comment!) as schema:rangeIncludes or a blanknode union of xsd:decimal and xsd:integer (because values will never be double-typed as both xsd:decimal and xsd:integer).

[HolgerKnublauch]

@TallTed This would be a job for SHACL-SHACL, using sh:datatype ( xsd:decimal xsd:integer ), not the main TTL file (which is only RDFS)

[VladimirAlexiev]

• Add Plantuml variant (re #166) #471 : the UML diagram simply says sh:order : number
  (this applies to PropertyShape and PropertyGroup)