Use JavaScript highlighting for Synax sections

Follows what MDN does, and makes things a bit easier to read.

docs/API.md

@@ -184,8 +184,10 @@ connection to a specified VNC server.
 
 ##### Syntax
 
+```js
 new RFB(target, urlOrChannel);
 new RFB(target, urlOrChannel, options);
+```
 
 ###### Parameters
 
@@ -323,7 +325,9 @@ and that the connection can continue.
 
 ##### Syntax
 
+```js
 RFB.approveServer();
+```
 
 #### RFB.blur()
 
@@ -333,7 +337,9 @@ point.
 
 ##### Syntax
 
+```js
 RFB.blur();
+```
 
 #### RFB.clipboardPasteFrom()
 
@@ -342,7 +348,9 @@ to the remote server.
 
 ##### Syntax
 
+```js
 RFB.clipboardPasteFrom(text);
+```
 
 ###### Parameters
 
@@ -356,7 +364,9 @@ connected server.
 
 ##### Syntax
 
+```js
 RFB.disconnect();
+```
 
 #### RFB.focus()
 
@@ -365,8 +375,10 @@ Keyboard events will be sent to the remote server after this point.
 
 ##### Syntax
 
+```js
 RFB.focus();
 RFB.focus(options);
+```
 
 ###### Parameters
 
@@ -386,7 +398,9 @@ the screen encoded as [`ImageData`][mdn-imagedata].
 
 ##### Syntax
 
+```js
 RFB.getImageData();
+```
 
 #### RFB.machineReboot()
 
@@ -396,7 +410,9 @@ to have any effect.
 
 ##### Syntax
 
+```js
 RFB.machineReboot();
+```
 
 #### RFB.machineReset()
 
@@ -406,7 +422,9 @@ to have any effect.
 
 ##### Syntax
 
+```js
 RFB.machineReset();
+```
 
 #### RFB.machineShutdown()
 
@@ -416,7 +434,9 @@ have any effect.
 
 ##### Syntax
 
+```js
 RFB.machineShutdown();
+```
 
 #### RFB.sendCredentials()
 
@@ -425,7 +445,9 @@ credentials after a `credentialsrequired` event has been fired.
 
 ##### Syntax
 
+```js
 RFB.sendCredentials(credentials);
+```
 
 ###### Parameters
 
@@ -441,7 +463,9 @@ around [`RFB.sendKey()`](#rfbsendkey).
 
 ##### Syntax
 
+```js
 RFB.sendCtrlAltDel();
+```
 
 #### RFB.sendKey()
 
@@ -449,8 +473,10 @@ The `RFB.sendKey()` method is used to send a key event to the server.
 
 ##### Syntax
 
+```js
 RFB.sendKey(keysym, code);
 RFB.sendKey(keysym, code, down);
+```
 
 ###### Parameters
 
@@ -479,9 +505,11 @@ screen encoded as [`Blob`][mdn-blob].
 
 ##### Syntax
 
+```js
 RFB.toBlob(callback);
 RFB.toBlob(callback, type);
 RFB.toBlob(callback, type, quality);
+```
 
 ###### Parameters
 
@@ -503,9 +531,11 @@ of an `img` tag.
 
 ##### Syntax
 
+```js
 RFB.toDataURL();
 RFB.toDataURL(type);
 RFB.toDataURL(type, encoderOptions);
+```
 
 ###### Parameters