Fix Objective-C highlighter.

Added Objective-C++ highlighter (SpartanJ/ecode#616).
Replaced "Treat .h file as C++" in favor of "Treat .h files as..." with multiple options, including auto-detection (SpartanJ/ecode#614).
Refresh semantic-highlighting after syntax highlighter change.

bin/assets/plugins/formatters.json

@@ -13,8 +13,8 @@
       "url": "https://prettier.io"
     },
     {
-      "language": ["c", "cpp", "objective-c", "java"],
-      "file_patterns": ["%.inl$", "%.cpp$", "%.hpp$", "%.cc$", "%.cxx$", "%.c++$", "%.hh$", "%.hxx$", "%.h++$", "%.objcpp$", "%.m$", "%.java$"],
+      "language": ["c", "cpp", "objective-c", "objective-cpp", "java"],
+      "file_patterns": ["%.inl$", "%.cpp$", "%.hpp$", "%.cc$", "%.cxx$", "%.c++$", "%.hh$", "%.hxx$", "%.h++$", "%.objcpp$", "%.m$", "%.mm$", "%.java$"],
       "command": "clang-format --style=file $FILENAME",
       "url": "https://clang.llvm.org/docs/ClangFormat.html",
       "prefer_lsp_formatter": true

bin/assets/plugins/lspclient.json

@@ -92,6 +92,12 @@
       "share_process": true,
       "file_patterns": ["%.m$"]
     },
+    {
+      "language": "objective-cpp",
+      "use": "clangd",
+      "share_process": true,
+      "file_patterns": ["%.mm$"]
+    },
     {
       "language": "d",
       "name": "serve-d",