Add documentation on v0 symbol mangling.

Author: ehuss

src/doc/rustc/book.toml

@@ -6,3 +6,6 @@ title = "The rustc book"
 [output.html]
 git-repository-url = "https://github.com/rust-lang/rust/tree/master/src/doc/rustc"
 edit-url-template = "https://github.com/rust-lang/rust/edit/master/src/doc/rustc/{path}"
+
+[output.html.playground]
+runnable = false

src/doc/rustc/src/SUMMARY.md

@@ -3,6 +3,7 @@
 - [What is rustc?](what-is-rustc.md)
 - [Command-line Arguments](command-line-arguments.md)
     - [Codegen Options](codegen-options/index.md)
+        - [Symbol Mangling](codegen-options/symbol-mangling.md)
 - [Lints](lints/index.md)
     - [Lint Levels](lints/levels.md)
     - [Lint Groups](lints/groups.md)

src/doc/rustc/src/codegen-options/index.md

@@ -569,13 +569,15 @@ for the purpose of generating object code and linking.
 
 Supported values for this option are:
 
-* `v0` — The "v0" mangling scheme. The specific format is not specified at
-  this time.
+* `v0` — The "v0" mangling scheme.
 
 The default, if not specified, will use a compiler-chosen default which may
 change in the future.
 
+See the [Symbol Mangling] chapter for details on symbol mangling and the mangling format.
+
 [name mangling]: https://en.wikipedia.org/wiki/Name_mangling
+[Symbol Mangling]: symbol-mangling.md
 
 ## target-cpu