Generalize over HTTP streams and refactor postable typeclass

Author: propensive

src/core/rudiments-core.scala

@@ -308,13 +308,13 @@ extension (bs: Long)
 extension (bytes: Bytes)
   def memory: Memory = Memory(bytes.size)
 
-def workingDirectory[PathType: Concretizable across Paths from Text]
+def workingDirectory[PathType: Instantiable across Paths from Text]
    (using directory: WorkingDirectory)
 :     PathType =
 
   directory.path[PathType]
 
-def homeDirectory[PathType: Concretizable across Paths from Text]
+def homeDirectory[PathType: Instantiable across Paths from Text]
    (using directory: HomeDirectory)
 :     PathType =
 

src/core/rudiments.HomeDirectory.scala

@@ -27,5 +27,5 @@ object HomeDirectory:
 trait HomeDirectory:
   def directory(): Text
 
-  def path[PathType: Concretizable across Paths from Text]: PathType =
+  def path[PathType: Instantiable across Paths from Text]: PathType =
     PathType(directory())

src/core/rudiments.WorkingDirectory.scala

@@ -31,5 +31,5 @@ object WorkingDirectory:
 trait WorkingDirectory:
   def directory(): Text
 
-  def path[PathType: Concretizable across Paths from Text]: PathType =
+  def path[PathType: Instantiable across Paths from Text]: PathType =
     PathType(directory())