add custom TTS playback speed

[ivan20203]

--> what:
the TTS (text to speech) speed has fixed settings of 0.25-0.5-0.75-1.00-1.25- and so on.

I implemented a custom speed option.
So now you will be able to type in numbers between 0 to 5 and with 2 decimal places.
So the value 1.1 will work.

--> how:
After setting up my the dev environment, this is where I had like 74 updates in git for making the files multi line.
I added it in BookReader/plugins/plugin.tts.js

After having a multiline implementation i asked ChatGPT to convert the new code i wrote into single line format that the current plugin.tts.js requires.

So thats where we are. After testing it I am now making a pull request.

Apologies for this if it was done the wrong way.

Pictures of working version below:

[ivan20203]

code changed:

From: BookReader.prototype.initNavbar=function(t){return function()
To: n.find(".BRcontrols .BRicon.zoom_out").closest("li"))}return n}}

changed in between them to add custom playback speed.

[ivan20203]

Edited wrong files. Edited plugin.tts.js in BookReader instead of src