[libc][docs] Add links to Peter Smith's FOSDEM 2025 talk (#129555)

Author: overmighty

libc/docs/talks.rst

@@ -1,6 +1,14 @@
 =====
 Talks
 =====
+----
+2025
+----
+* An introduction to building and using LLVM libc - Peter Smith
+
+  * `slides <https://fosdem.org/2025/events/attachments/fosdem-2025-5456-an-introduction-to-building-and-using-llvm-libc/slides/237989/Fosdem202_76Bilu2.pdf>`__
+  * `videos <https://fosdem.org/2025/schedule/event/fosdem-2025-5456-an-introduction-to-building-and-using-llvm-libc/>`__
+
 ----
 2024
 ----