Gifs and screenshots for features in manual (syntax highlighting and typing)

crates/ide/src/syntax_highlighting.rs

@@ -48,6 +48,8 @@ pub struct HlRange {
 //
 // The general rule is that a reference to an entity gets colored the same way as the entity itself.
 // We also give special modifier for `mut` and `&mut` local variables.
+//
+// image::https://user-images.githubusercontent.com/48062697/113164457-06cfb980-9239-11eb-819b-0f93e646acf8.png[]
 pub(crate) fn highlight(
     db: &RootDatabase,
     file_id: FileId,

crates/ide/src/typing.rs

@@ -49,6 +49,8 @@ pub(crate) const TRIGGER_CHARS: &str = ".=>";
 // ----
 // "editor.formatOnType": true,
 // ----
+//
+// image::https://user-images.githubusercontent.com/48062697/113166163-69758500-923a-11eb-81ee-eb33ec380399.gif[]
 pub(crate) fn on_char_typed(
     db: &RootDatabase,
     position: FilePosition,