fix the name of thread.available_parallelism in Binary.md (#428)

see #419

Author: liigo

design/mvp/Binary.md

@@ -287,7 +287,7 @@ canon    ::= 0x00 0x00 f:<core:funcidx> opts:<opts> ft:<typeidx> => (canon lift
            | 0x07 rt:<typdidx>                                   => (canon resource.drop rt async (core func))
            | 0x04 rt:<typeidx>                                   => (canon resource.rep rt (core func))
            | 0x05 ft:<typeidx>                                   => (canon thread.spawn ft (core func)) 🧵
-           | 0x06                                                => (canon thread.available_concurrency (core func)) 🧵
+           | 0x06                                                => (canon thread.available_parallelism (core func)) 🧵
            | 0x08                                                => (canon task.backpressure (core func)) 🔀
            | 0x09 ft:<core:typeidx>                              => (canon task.return ft (core func)) 🔀
            | 0x0a async?:<async>? m:<core:memdix>                => (canon task.wait async? (memory m) (core func)) 🔀