Updated gitignore

.gitignore

@@ -1,12 +1,12 @@
-build/CMakeFiles
-build/Testing/Temporary
-build/cpputest
-build/src
-build/tests
-build/CMakeCache.txt
-build/CTestTestfile.cmake
-build/Makefile
-build/cmake_install.cmake
-build/compile_commands.json
-.cache/clangd/index
-build/.cache/clangd/index
+.cache/
+*.core
+tags
+
+# Keep the build directory itself.
+build/*
+
+# Generated Documentation shouldn't be included.
+docs/generated_docs/latex
+docs/generated_docs/html
+
+