[docs] Fused AWQ modules

[stevhliu]

Streamlines the quantization docs a bit with the latest AWQ-fused module update :)

• I think the reintroduced Benchmarks in the AWQ section is a duplicate because it's already currently at the end of the doc. I moved the Benchmarks to the end because I think comparing the results of all the quantization schemes makes more sense after having read through them. Looking at the benchmarks now in the AWQ section, you don't have as much context about the other quantization schemes (AutoGPTQ, bitsandbytes), making it a bit more difficult to compare IMO.
• condense the fused/unfused code with the code-switching feature in the docs
• try to improve the table titles of the fused/unfused benchmarks

[younesbelkada]

Makes sense, thanks @stevhliu !

[ArthurZucker]

Nice 🔥