Auto merge of #83185 - jyn514:remove-dead-code, r=oli-obk

Remove (lots of) dead code

Builds on
- [ ] rust-lang/rust#83161
- [x] rust-lang/rust#83230
- [x] rust-lang/rust#83197.

Found with https://github.com/est31/warnalyzer.
See rust-lang/rust#77739 for a similar change in the past.

Dubious changes:
- Maybe some of the dead code in rustc_data_structures should be kept, in case someone wants to use it in the future?

TODO:
- [ ] check if any of the comments on the deleted code should be kept.
- [x] update the compiler documentation; right now it fails to build
- [x] finish moving `cfg(test)` changes into rust-lang/rust#83197

cc `@est31`

src/lib.rs

@@ -413,10 +413,6 @@ impl<'a> Id<'a> {
     pub fn as_slice(&'a self) -> &'a str {
         &*self.name
     }
-
-    pub fn name(self) -> Cow<'a, str> {
-        self.name
-    }
 }
 
 /// Each instance of a type that implements `Label<C>` maps to a
@@ -484,10 +480,6 @@ impl<'a> LabelText<'a> {
         LabelStr(s.into())
     }
 
-    pub fn escaped<S: Into<Cow<'a, str>>>(s: S) -> LabelText<'a> {
-        EscStr(s.into())
-    }
-
     pub fn html<S: Into<Cow<'a, str>>>(s: S) -> LabelText<'a> {
         HtmlStr(s.into())
     }
@@ -543,11 +535,6 @@ impl<'a> LabelText<'a> {
         }
     }
 
-    /// Puts `prefix` on a line above this label, with a blank line separator.
-    pub fn prefix_line(self, prefix: LabelText<'_>) -> LabelText<'static> {
-        prefix.suffix_line(self)
-    }
-
     /// Puts `suffix` on a line below this label, with a blank line separator.
     pub fn suffix_line(self, suffix: LabelText<'_>) -> LabelText<'static> {
         let mut prefix = self.pre_escaped_content().into_owned();
@@ -602,11 +589,6 @@ pub enum RenderOption {
     DarkTheme,
 }
 
-/// Returns vec holding all the default render options.
-pub fn default_options() -> Vec<RenderOption> {
-    vec![]
-}
-
 /// Renders directed graph `g` into the writer `w` in DOT syntax.
 /// (Simple wrapper around `render_opts` that passes a default set of options.)
 pub fn render<'a, N, E, G, W>(g: &'a G, w: &mut W) -> io::Result<()>

src/tests.rs

@@ -111,7 +111,7 @@ impl<'a> Labeller<'a> for LabelledGraph {
     fn node_label(&'a self, n: &Node) -> LabelText<'a> {
         match self.node_labels[*n] {
             Some(l) => LabelStr(l.into()),
-            None => LabelStr(id_name(n).name()),
+            None => LabelStr(id_name(n).name),
         }
     }
     fn edge_label(&'a self, e: &&'a Edge) -> LabelText<'a> {