fix manual

Author: matklad

manual.adoc

@@ -18,10 +18,7 @@ To improve this document, send a pull request: +
 https://github.com/rust-analyzer/rust-analyzer/blob/master/docs/user/manual.adoc[https://github.com/rust-analyzer/.../manual.adoc]
 
 The manual is written in https://asciidoc.org[AsciiDoc] and includes some extra files which are generated from the source code. Run `cargo test` and `cargo test -p xtask` to create these and then `asciidoctor manual.adoc` to create an HTML copy.
-
-// IMPORTANT: master copy of this document lives in the https://github.com/rust-analyzer/rust-analyzer repository
-
-===
+====
 
 If you have questions about using rust-analyzer, please ask them in the https://users.rust-lang.org/c/ide/14["`IDEs and Editors`"] topic of Rust users forum.