#134: Legend fill whitespace with SHOW_FLOATING_LEGEND() and Lay_Distance()

[kirchsth]

With following new macros existing whitespaces can be reused

• `SHOW_FLOATING_LEGEND(?alias, ?hideStereotype): shows the legend in the drawing area

• LEGEND(): is the default alias of the created floating legend and can be used in Lay_Distance() call

• Lay_Distance(from, to, ?distance): Sets the distance between from and to with down alignment (Lay_Distance(from,to,0) equals Lay_D(from, to)). The default alias of the floating legend is LEGEND().

like in the sample based on my extended branch

@startuml
!include https://raw.githubusercontent.com/kirchsth/C4-PlantUML/extended/C4_Container.puml

Person(a, "Person A")
Container(b, "Container B", "techn")
System(c, "System C")
Container(d, "Container D", "techn")
Container_Ext(e, "Ext. Container E", "techn")

Rel_R(a, b, "calls")
Rel_D(b, c, "uses")
Rel_D(c, d, "uses")
Rel_R(d, e, "updates")

SHOW_FLOATING_LEGEND()
Lay_Distance(LEGEND(), e, 1)

SHOW_FLOATING_LEGEND(legend2)
Lay_Distance(a, legend2, 1)
@enduml

techn. details: "legend" is a reserved word and cannot be used as (default) alias, therefore I added the LEGEND() macro

BR Helmut