Cpp extensions (#1451)

* Add more cpp extensions

* Allow FilenameMatcher to be case insensitive
---------

Co-authored-by: Darin Morrison <darinmorrison@gmail.com>
Co-authored-by: silvanshade <silvanshade@users.noreply.github.com>
Co-authored-by: MischaPanch

test/solidlsp/cpp/test_ccls_languages.py

@@ -0,0 +1,24 @@
+import os
+
+import pytest
+
+from solidlsp.ls_config import Language
+from test.conftest import start_ls_context
+
+
+@pytest.mark.cpp
+class TestCCLSLanguages:
+    @pytest.mark.parametrize(
+        "lang, unit, names",
+        [
+            ("C", "a.c", {"main"}),
+            ("Objective-C", "a.m", {"main", "Hello", "-hello"}),
+        ],
+    )
+    def test_get_document_symbols(self, lang: str, unit: str, names: set[str]) -> None:
+        with start_ls_context(Language.CPP) as ccls:
+            path = os.path.join(lang, unit)
+            symbols = ccls.request_document_symbols(path).get_all_symbols_and_roots()
+            symbols = symbols[0] if symbols and isinstance(symbols[0], list) else symbols
+            symbols = {s.get("name") for s in symbols}
+            assert names == symbols, f"Expected '{names}' in document symbols, got: {symbols}"