fix hard edge (renamed: transition) for cmd_10()

[slagernate]

asciiwave behaviour does not match wavedrom when specifying high / low signals. E.g. running $ ./asciiwave example/step7.json produces:

         ┌─┐ ┌─┐ ┌─┐ ┌─┐ ┌─┐ 
clk    : ┘ └─┘ └─┘ └─┘ └─┘ └─
         xxxx╱  ╲╱  ╲╱  ╲xxxx
Data   : xxxx╲he╱╲bo╱╲ta╱xxxx
         ┐   ┌───────────┐   
Request: └───┘           └───

Here the Request signal mistakenly has a transition to start. E.g. if we copy the following into wavedrom, there is no clock transition at the start for Request.

{ signal: [
  { name: "clk",     wave: "p...." },
  { name: "Data",    wave: "x345x",  data: ["head", "body", "tail"] },
  { name: "Request", wave: "01..0" }
  ],
  config: { hscale: 1 }
}

with this PR, asciiwave more closely mimicks wavedrom:

$ ./asciiwave example/step7.json produces:

         ┌─┐ ┌─┐ ┌─┐ ┌─┐ ┌─┐ 
clk    : ┘ └─┘ └─┘ └─┘ └─┘ └─
         xxxx╱  ╲╱  ╲╱  ╲xxxx
Data   : xxxx╲he╱╲bo╱╲ta╱xxxx
             ┌───────────┐   
Request: ────┘           └───