doc: fix wording (cr)

Co-authored-by: D. Ben Knoble <[email protected]>

qi-doc/scribblings/principles.scrbl

@@ -37,7 +37,7 @@
 
 @section{Flows as Graphs}
 
- A flow could also be considered an @hyperlink["https://en.wikipedia.org/wiki/Directed_acyclic_graph"]{acyclic graph}, with its component flows as nodes, and a directed edge connecting two flows if an output of one is used as an input of the other. There may be many distinct @deftech{paths} that could be traced over this graph, and we may imagine values to flow along these paths at runtime (although of course, @seclink["Values_and_Flows"]{there is nothing that flows}). At each point in the flow (in this spatial sense), there is a certain number of values present, depending on the runtime inputs. We refer to this number as the @deftech{arity} or the @deftech{volume} of the flow at that point. Volume is a runtime concept since it depends on the actual inputs provided to the flow, although there may be cases where it could be determined at compile time.
+ A flow could also be considered an @hyperlink["https://en.wikipedia.org/wiki/Directed_acyclic_graph"]{acyclic graph}, with its component flows as nodes, and a directed edge connecting two flows if an output of one is used as an input of the other. There may be many distinct @deftech{paths} that could be traced over this graph, and we may imagine values to flow along these paths at runtime (although of course, @seclink["Values_and_Flows"]{there is nothing that flows}). At each point in the flow (in this spatial sense), there are a certain number of values present, depending on the runtime inputs. We refer to this number as the @deftech{arity} or the @deftech{volume} of the flow at that point. Volume is a runtime concept since it depends on the actual inputs provided to the flow, although there may be cases where it could be determined at compile time.
 
 @section{Values are Not Collections}