Moved the String format constants from the Pathable protocol in the library target into its own String+Constants extension.

Library/Sources/Internal/Extensions/String+Constants.swift

@@ -0,0 +1,8 @@
+extension String {
+    enum Format {
+        enum Path {
+            static let docs = "/docs/%@"
+            static let root = "/%@"
+        }
+    }
+}