Add tracking issue to docs

Author: wesleywiser

Diff for: src/doc/unstable-book/src/compiler-flags/dwarf-version.md

@@ -1,5 +1,9 @@
 ## `dwarf-version`
 
+The tracking issue for this feature is: <https://github.com/rust-lang/rust/issues/103057>
+
+----------------------------
+
 This option controls the version of DWARF that the compiler emits, on platforms
 that use DWARF to encode debug information. It takes one of the following
 values: