Bug 1254234 - Make narrate speed slider range more useful. r=Gijs

MozReview-Commit-ID: KyKxLstRPVD

--HG--
extra : rebase_source : 637f2aa7fe2f46571cfa1b35eaf2941026a233a6

toolkit/components/narrate/NarrateControls.jsm

@@ -53,7 +53,7 @@ function NarrateControls(mm, win) {
       </div>
       <div id="narrate-rate" class="narrate-row">
         <input id="narrate-rate-input" value="0" title="${"speed"}"
-               step="25" max="400" min="-400" type="range">
+               step="25" max="100" min="-100" type="range">
       </div>
       <div id="narrate-voices" class="narrate-row"></div>
       <div class="dropdown-arrow"></div>