feat: Use markdown for hover text and add well known types hover documentations (#44)

Author: coder3101

sample/simple.proto

@@ -13,7 +13,11 @@ message Book {
   google.protobuf.Any data = 4;
   BookState state = 5;
 
-  // Author is a author of a book
+  // # Author is a author of a book
+  // Usage is as follow:
+  // ```rust
+  // println!("hello world")
+  // ```
   message Author {
     string name = 1;
     int64 age = 2;

src/lsp.rs

@@ -175,23 +175,16 @@ impl LanguageServer for ProtoLanguageServer {
             return Box::pin(async move { Ok(None) });
         };
 
-        let comments = self
+        let result = self
             .state
             .hover(current_package_name.as_ref(), identifier.as_ref());
 
-        let response = match comments.len() {
-            0 => None,
-            1 => Some(Hover {
-                contents: HoverContents::Scalar(comments[0].clone()),
-                range: None,
-            }),
-            2.. => Some(Hover {
-                contents: HoverContents::Array(comments),
+        Box::pin(async move {
+            Ok(result.map(|r| Hover {
                 range: None,
-            }),
-        };
-
-        Box::pin(async move { Ok(response) })
+                contents: HoverContents::Markup(r),
+            }))
+        })
     }
     fn completion(
         &mut self,

src/parser/hover.rs

@@ -47,7 +47,7 @@ impl ParsedTree {
         }
     }
 
-    pub fn hover(&self, identifier: &str, content: impl AsRef<[u8]>) -> Vec<MarkedString> {
+    pub fn hover(&self, identifier: &str, content: impl AsRef<[u8]>) -> Vec<String> {
         let mut results = vec![];
         self.hover_impl(identifier, self.tree.root_node(), &mut results, content);
         results
@@ -57,7 +57,7 @@ impl ParsedTree {
         &self,
         identifier: &str,
         n: Node,
-        v: &mut Vec<MarkedString>,
+        v: &mut Vec<String>,
         content: impl AsRef<[u8]>,
     ) {
         if identifier.is_empty() {
@@ -77,14 +77,13 @@ impl ParsedTree {
                 }
             }
             None => {
-                let comments: Vec<MarkedString> = self
+                let comments: Vec<String> = self
                     .filter_nodes_from(n, NodeKind::is_userdefined)
                     .into_iter()
                     .filter(|n| {
                         n.utf8_text(content.as_ref()).expect("utf-8 parse error") == identifier
                     })
                     .filter_map(|n| self.find_preceding_comments(n.id(), content.as_ref()))
-                    .map(MarkedString::String)
                     .collect();
 
                 v.extend(comments);