Game crashes on startup when render key is set to any of the mouse buttons

[2xsaiko]

This happens because Minecraft uses -100 and lower for mouse buttons and Keyboard.isKeyDown doesn't know what do as it isn't an actual key

java.lang.IndexOutOfBoundsException: -100
    at java.nio.DirectByteBuffer.get(DirectByteBuffer.java:253)
    at org.lwjgl.input.Keyboard.isKeyDown(Keyboard.java:407)
    at com.unascribed.blockrenderer.BlockRenderer.onFrameStart(BlockRenderer.java:98)
    at net.minecraftforge.fml.common.eventhandler.ASMEventHandler_12_BlockRenderer_onFrameStart_RenderTickEvent.invoke(.dynamic)
    at net.minecraftforge.fml.common.eventhandler.ASMEventHandler.invoke(ASMEventHandler.java:90)
    at net.minecraftforge.fml.common.eventhandler.EventBus.post(EventBus.java:185)
    at net.minecraftforge.fml.common.FMLCommonHandler.onRenderTickStart(FMLCommonHandler.java:350)
    at net.minecraft.client.Minecraft.runGameLoop(Minecraft.java:1137)
    at net.minecraft.client.Minecraft.run(Minecraft.java:406)
    at net.minecraft.client.main.Main.main(Main.java:118)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at net.minecraft.launchwrapper.Launch.launch(Launch.java:135)
    at net.minecraft.launchwrapper.Launch.main(Launch.java:28)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at net.minecraftforge.gradle.GradleStartCommon.launch(GradleStartCommon.java:97)
    at GradleStart.main(GradleStart.java:26)

[unascribed]

Confirmed not to affect the 1.16 port.