Insert a newline for empty single-line documentation comments

CHANGELOG.md

@@ -6,6 +6,10 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 
 ## [Unreleased]
 
+### Fixed
+
+- Single-line documentation comments (`---`) now correctly preserve newlines ([#917](https://github.com/JohnnyMorganz/luau-lsp/pull/917)).
+
 ## [1.39.1] - 2025-02-08
 
 ### Fixed

src/DocumentationParser.cpp

@@ -405,6 +405,10 @@ std::vector<std::string> WorkspaceFolder::getComments(const Luau::ModuleName& mo
             {
                 comments.emplace_back(commentText.substr(4));
             }
+            else if (commentText == "---")
+            {
+                comments.emplace_back("\n");
+            }
         }
         else if (comment.type == Luau::Lexeme::Type::BlockComment)
         {

tests/Documentation.test.cpp

@@ -483,4 +483,27 @@ TEST_CASE_FIXTURE(Fixture, "ignored_tags")
                             "\n- `x` number -- Testing");
 }
 
+TEST_CASE_FIXTURE(Fixture, "singleline_comments_preserve_newlines")
+{
+    auto result = check(R"(
+        --- @class MyClass
+        ---
+        --- A sample class.
+        local MyClass = {}
+    )");
+
+    REQUIRE_EQ(0, result.errors.size());
+
+    auto ty = requireType("MyClass");
+    auto ttv = Luau::get<Luau::TableType>(ty);
+    REQUIRE(ttv);
+
+    auto comments = getComments(ttv->definitionLocation);
+    REQUIRE_EQ(3, comments.size());
+
+    CHECK_EQ("@class MyClass", comments[0]);
+    CHECK_EQ("\n", comments[1]);
+    CHECK_EQ("A sample class.", comments[2]);
+}
+
 TEST_SUITE_END();