Add language fences around markdown code blocks

Completes fix for #694

Author: lukaszsamson

apps/language_server/lib/language_server/providers/completion.ex

@@ -650,7 +650,7 @@ defmodule ElixirLS.LanguageServer.Providers.Completion do
 
     formatted_spec =
       if type_spec != "" do
-        "```\n#{type_spec}\n```\n"
+        "```elixir\n#{type_spec}\n```\n"
       else
         ""
       end
@@ -672,7 +672,7 @@ defmodule ElixirLS.LanguageServer.Providers.Completion do
 
     formatted_spec =
       if expanded_spec != "" do
-        "\n\n```\n#{expanded_spec}\n```\n"
+        "\n\n```elixir\n#{expanded_spec}\n```\n"
       else
         ""
       end
@@ -729,7 +729,7 @@ defmodule ElixirLS.LanguageServer.Providers.Completion do
 
     formatted_spec =
       if spec != "" do
-        "\n\n```\n#{spec}\n```\n"
+        "\n\n```elixir\n#{spec}\n```\n"
       else
         ""
       end

apps/language_server/lib/language_server/source_file.ex

@@ -223,7 +223,7 @@ defmodule ElixirLS.LanguageServer.SourceFile do
 
     """
 
-    ```
+    ```elixir
     #{spec_str}
     ```
     """

apps/language_server/test/providers/completion_test.exs

@@ -1135,7 +1135,7 @@ defmodule ElixirLS.LanguageServer.Providers.CompletionTest do
                :kind => "markdown",
                "value" => """
                The summary
-               ```
+               ```elixir
                @spec add(
                        a_big_name ::
                          integer(),

apps/language_server/test/server_test.exs

@@ -1609,7 +1609,7 @@ defmodule ElixirLS.LanguageServer.ServerTest do
                        """
                        Inspects and writes the given `item` to the device.
 
-                       ```
+                       ```elixir
                        @spec inspect\
                        """ <> _
                    },
@@ -1622,7 +1622,7 @@ defmodule ElixirLS.LanguageServer.ServerTest do
                      "value" => """
                      Inspects `item` according to the given options using the IO `device`.
 
-                     ```
+                     ```elixir
                      @spec inspect(device(), item, keyword()) ::
                              item
                            when item: var

apps/language_server/test/source_file_test.exs

@@ -17,7 +17,7 @@ defmodule ElixirLS.LanguageServer.SourceFileTest do
 
     assert SourceFile.format_spec(spec, line_length: 80) == """
 
-           ```
+           ```elixir
            @spec format_spec(String.t(), keyword()) :: String.t()
            ```
            """
@@ -28,7 +28,7 @@ defmodule ElixirLS.LanguageServer.SourceFileTest do
 
     assert SourceFile.format_spec(spec, line_length: 30) == """
 
-           ```
+           ```elixir
            @spec format_spec(
                    String.t(),
                    keyword()

dep_versions.exs

@@ -1,5 +1,5 @@
 [
-  elixir_sense: "d2e39a51542dec75932a20cdf430acff24896087",
+  elixir_sense: "c47f948cdcb716c5757fdbdc9badfdd034a6613c",
   dialyxir_vendored: "d50dcd7101c6ebd37b57b7ee4a7888d8cb634782",
   jason_v: "c81537e2a5e1acacb915cf339fe400357e3c2aaa",
   erl2ex_vendored: "073ac6b9a44282e718b6050c7b27cedf9217a12a",

mix.lock

@@ -2,7 +2,7 @@
   "benchee": {:hex, :benchee, "1.1.0", "f3a43817209a92a1fade36ef36b86e1052627fd8934a8b937ac9ab3a76c43062", [:mix], [{:deep_merge, "~> 1.0", [hex: :deep_merge, repo: "hexpm", optional: false]}, {:statistex, "~> 1.0", [hex: :statistex, repo: "hexpm", optional: false]}], "hexpm", "7da57d545003165a012b587077f6ba90b89210fd88074ce3c60ce239eb5e6d93"},
   "deep_merge": {:hex, :deep_merge, "1.0.0", "b4aa1a0d1acac393bdf38b2291af38cb1d4a52806cf7a4906f718e1feb5ee961", [:mix], [], "hexpm", "ce708e5f094b9cd4e8f2be4f00d2f4250c4095be93f8cd6d018c753894885430"},
   "dialyxir_vendored": {:git, "https://github.com/elixir-lsp/dialyxir.git", "d50dcd7101c6ebd37b57b7ee4a7888d8cb634782", [ref: "d50dcd7101c6ebd37b57b7ee4a7888d8cb634782"]},
-  "elixir_sense": {:git, "https://github.com/elixir-lsp/elixir_sense.git", "d2e39a51542dec75932a20cdf430acff24896087", [ref: "d2e39a51542dec75932a20cdf430acff24896087"]},
+  "elixir_sense": {:git, "https://github.com/elixir-lsp/elixir_sense.git", "c47f948cdcb716c5757fdbdc9badfdd034a6613c", [ref: "c47f948cdcb716c5757fdbdc9badfdd034a6613c"]},
   "erl2ex_vendored": {:git, "https://github.com/elixir-lsp/erl2ex.git", "073ac6b9a44282e718b6050c7b27cedf9217a12a", [ref: "073ac6b9a44282e718b6050c7b27cedf9217a12a"]},
   "erlex_vendored": {:git, "https://github.com/elixir-lsp/erlex.git", "82db0e82ee4896491bc26dec99f5d795f03ab9f4", [ref: "82db0e82ee4896491bc26dec99f5d795f03ab9f4"]},
   "jason_v": {:git, "https://github.com/elixir-lsp/jason.git", "c81537e2a5e1acacb915cf339fe400357e3c2aaa", [ref: "c81537e2a5e1acacb915cf339fe400357e3c2aaa"]},