Use --- so that it actually shows up as an em dash lol

README.md

@@ -17,7 +17,7 @@ You'll need:
 
 - [WABT](https://github.com/WebAssembly/wabt)
 - [Guile](https://www.gnu.org/software/guile/) (or bring your own HTTP
-  server -- see note below)
+  server --- see note below)
 
 To run, first compile the WebAssembly module:
 
@@ -60,7 +60,7 @@ registers: `xBUF`, `xHEAD` and `xTAIL`:
   data, and `xTAIL` being the offset of the first byte *after* the data.
 
 In order to be distinguishable from the empty state, the ring buffers
-must never be completely full -- there must always be *at least one*
+must never be completely full --- there must always be *at least one*
 unoccupied byte between the tail and the head.
 
 ### System status