Citation links in preparation for PR suggestions

Author: BatmanAoD

src/items/functions.md

@@ -230,6 +230,7 @@ implementation.
 > aborts the process by executing an illegal instruction.
 
 [panic-modes]: ../panic.md#panic-runtimes
+[Undefined Behavior]: ../behavior-considered-undefined.md
 
 ## Const functions
 

src/linkage.md

@@ -231,3 +231,4 @@ runtime, so this prohibition does not apply to projects compiled with Cargo.
 [configuration option]: conditional-compilation.md
 [procedural macros]: procedural-macros.md
 [panic-runtime]: panic.md#panic-runtimes
+[`ffi_unwind_calls` lint]: ../rustc/lints/listing/allowed-by-default.html#ffi-unwind-calls

src/panic.md

@@ -4,7 +4,7 @@ Rust provides the ability to "panic" upon encountering a runtime error that is
 not part of a function's signature; such an error is typically not expected to
 be recoverable within the context in which the error is encountered.
 
-> The Standard Library provides this capability via the [`panic!` macro][macro-panic].
+> **Note**: The Standard Library provides this capability via the [`panic!` macro][macro-panic].
 
 Although it is not part of the core language, panics interact with several core
 language features; for instance, out-of-bounds array indexing using the