Build rust-analyzer proc-macro server by default

This allows getting rid of some documentation and an extra step when building a custom toolchain: https://rustc-dev-guide.rust-lang.org/building/how-to-build-and-run.html#creating-a-rustup-toolchain
and it seems likely that people will want to do this if they want rustdoc (which is also built by default).

Author: jyn514

src/bootstrap/tool.rs

@@ -747,19 +747,9 @@ impl Step for RustAnalyzerProcMacroSrv {
     const ONLY_HOSTS: bool = true;
 
     fn should_run(run: ShouldRun<'_>) -> ShouldRun<'_> {
-        let builder = run.builder;
-
         // Allow building `rust-analyzer-proc-macro-srv` both as part of the `rust-analyzer` and as a stand-alone tool.
         run.path("src/tools/rust-analyzer")
             .path("src/tools/rust-analyzer/crates/proc-macro-srv-cli")
-            .default_condition(
-                builder.config.extended
-                    && builder.config.tools.as_ref().map_or(true, |tools| {
-                        tools.iter().any(|tool| {
-                            tool == "rust-analyzer" || tool == "rust-analyzer-proc-macro-srv"
-                        })
-                    }),
-            )
     }
 
     fn make_run(run: RunConfig<'_>) {