Add documentation for rustdoc --no-source flag

Author: GuillaumeGomez

Diff for: src/doc/rustdoc/src/command-line-arguments.md

@@ -417,3 +417,21 @@ This flag is **deprecated** and **has no effect**.
 Rustdoc only supports Rust source code and Markdown input formats. If the
 file ends in `.md` or `.markdown`, `rustdoc` treats it as a Markdown file.
 Otherwise, it assumes that the input file is Rust.
+
+## `--no-source`: prevent source code generation in HTML output format generation
+
+Using this flag looks like this:
+
+```bash
+$ rustdoc src/lib.rs --no-source
+```
+
+By default, `rustdoc` renders the source code as HTML and links to it from the documentation. When
+this flag is used, `rustdoc` won't render the source code. `--no-source` is equivalent to the
+`#![doc(html_no_source)]` attribute:
+
+```rust
+// lib.rs
+#![doc(html_no_source)]
+// your code
+```

Diff for: src/librustdoc/lib.rs

@@ -533,6 +533,8 @@ fn opts() -> Vec<RustcOptGroup> {
                 "emit",
                 "Comma separated list of types of output for rustdoc to emit",
                 "[unversioned-shared-resources,toolchain-shared-resources,invocation-specific]",
+            )
+        }),
         stable("no-source", |o| {
             o.optflag(
                 "",