Don't double semantic highlight some comments.

spec/compilers/directives/highlight-comments-multiple

@@ -0,0 +1,49 @@
+component Main {
+  fun render : Html {
+    @highlight {
+      // Comment1
+      // Comment2
+      ""
+    }[1]
+  }
+}
+--------------------------------------------------------------------------------
+import {
+  createElement as B,
+  fragment as C
+} from "./runtime.js";
+
+export const A = () => {
+  return [
+    ``,
+    B(C, {}, [
+      B("span", {
+        className: "line"
+      }, [
+        B("span", {
+          className: "comment"
+        }, [`// Comment1`]),
+        `
+`
+      ]),
+      B("span", {
+        className: "line"
+      }, [
+        ``,
+        B("span", {
+          className: "comment"
+        }, [`// Comment2`]),
+        `
+`
+      ]),
+      B("span", {
+        className: "line"
+      }, [
+        ``,
+        B("span", {
+          className: "string"
+        }, [`""`])
+      ])
+    ])
+  ][1]
+};

spec/formatters/comment_multiple_3

@@ -0,0 +1,15 @@
+module Test {
+  fun test : String {
+    // Comment E
+    // Comment F
+    ""
+  }
+}
+--------------------------------------------------------------------------------
+module Test {
+  fun test : String {
+    // Comment E
+    // Comment F
+    ""
+  }
+}

src/formatter/processor.cr

@@ -123,7 +123,9 @@ module Mint
             # TODO: Check if all of the conditions are still needed.
             if last
               space_separated =
-                last && Ast.space_separated?(last, item)
+                last &&
+                  !last.is_a?(Ast::Comment) &&
+                  Ast.space_separated?(last, item)
 
               comments_and_one_is_block =
                 last.is_a?(Ast::Comment) &&

src/parsers/comment.cr

@@ -2,7 +2,7 @@ module Mint
   class Parser
     def comment : Ast::Comment?
       parse do |start_position|
-        content, type, next_comment =
+        content, type, next_comment, to =
           if word! "/*"
             consumed =
               gather { consume { !word?("*/") && !eof? } }.to_s
@@ -12,21 +12,24 @@ module Mint
               snippet self
             end unless word! "*/"
 
-            {consumed, Ast::Comment::Type::Block, nil}
+            {consumed, Ast::Comment::Type::Block, nil, position}
           elsif word! "//"
             consumed =
               gather { consume { char != '\n' && !eof? } }.to_s
 
+            to_position =
+              position
+
             comment =
               parse do
                 spaces = gather { whitespace }.to_s
                 next unless word?("//") && spaces.count('\n') == 1
                 self.comment
               end
 
-            {consumed, Ast::Comment::Type::Inline, comment}
+            {consumed, Ast::Comment::Type::Inline, comment, to_position}
           else
-            {nil, Ast::Comment::Type::Block, nil}
+            {nil, Ast::Comment::Type::Block, nil, position}
           end
 
         next unless content
@@ -35,9 +38,9 @@ module Mint
           next_comment: next_comment,
           from: start_position,
           content: content,
-          to: position,
           type: type,
-          file: file)
+          file: file,
+          to: to)
       end
     end
   end