Do some reorganization of the docs with the goals of:

• keeping a linear tutorial flow, visiting certain topics multiple times to build up understanding
• deduplicating material
• removing the “User guides” and “Advanced guides” sections and work the material into the tutorials

Tasks are:

• Merge How to Think in JAX with Key Concepts into a new intro section
• Split “Control flow” out of Sharp Bits into its own tutorial
  • Add an example for logical operators to the Control Flow tutorial
• Other changes to Sharp Bits
  • Remove or cut down parts on PRNG/NaNs since these are handled elsewhere
  • Move the discussion of jitting class methods from FAQ to Sharp Bits
  • Add a note about not jitting functions that close over large arrays
• New tutorial on Tracing (drawing from “How to Think in JAX” and “Different Kinds of JAX Values” in the FAQ)
• Add an example with register_dataclasses to the pytrees tutorial
• Move “Controlling data and computation placement on devices” from FAQ to Intro to parallel programming
• Split “Custom Pytrees” off of the pytrees tutorial and into its own Advanced section
• Split up Advanced AD into sections
• Reorganize the User Guides and Advanced Guides into “Getting Started > Tutorials” and “Resources and Advanced Tutorials”
• Move “Buffer donation” from FAQ to a new section under “Performance optimizations”
• Move “Benchmarking” from FAQ to a new section under “Performance benchmarking and profiling”
• Remove material from “Parallel Computation” that overlaps with “Introduction to Parallel Programming”
• Introduce jax.debug.print and jax.debug.breakpoint in a short Debugging section in Quickstart

Complements #18585