Standardize bibliographic citations in docs

[pierwill]

There are several bibliographic citations in the rustc API docs (examples here, here, and here). I'd like to propose standardizing these references.

Citation styles can inspire strong feelings. The Chicago Manual of Style provides a style that is especially flexible and attractive. Example: Matthew Flatt et al., “Macros That Work Together: Compile-Time Bindings, Partial Expansion, and Definition Contexts,” *Journal of Functional Programming* 22, no. 2 (March 1, 2012): 181–216, doi:10.1017/S0956796812000093.

[JohnTitor]

Closing as fixed by #73881.