Fix grammar, spelling, and typos

[henrybear327]

Summary by cubic

Fixes grammar, spelling, and LaTeX rendering across the concurrency primer, and tidies the C examples. Renames a misspelled thread‑pool flag and polishes comments/messages; no behavior changes.

• Bug Fixes
  • LaTeX: corrected typos and wording; fixed math-mode and figure/caption formatting (e.g., $t1 \to t2$); clarified RMW/CAS/memory-order/progress sections; added a note on x86‑64 -mcx16 and possible -latomic requirement.
  • C examples: renamed initialezed to initialized and updated all references; refined comments and prints (e.g., “asks/waits,” BBP note).

^{Written for commit 5497fac. Summary will update on new commits.}