Auto merge of #62457 - zackmdavis:minimax_search_and_the_structure_of_cognition,...

pretty-pretty extremal constants!

(A resurrection of the defunct #57073.)

While many programmers may intuitively appreciate the significance of "magic numbers" like −2147483648, Rust is about empowering everyone to build reliable and efficient software! It's a bit more legible to print the constant names (even noisy fully-qualified-paths thereof).

The bit-manipulation methods mirror those in `librustc_mir::hair::pattern::_match::all_constructors`; thanks to the immortal Varkor for guidance.

Resolves #56393.

r? @varkor