[clangd] Add README pointing to docs, bugtracker etc. NFC

clang-tools-extra/clangd/README.md

@@ -0,0 +1,19 @@
+## clangd
+
+clangd is a language server, and provides C++ IDE features to editors.
+This is not its documentation.
+
+- the **website** is https://clangd.llvm.org/.
+- the **bug tracker** is https://github.com/clangd/clangd/issues
+- the **source code** is hosted at https://github.com/llvm/llvm-project/tree/master/clang-tools-extra/clangd.
+- the **website source code** is at https://github.com/llvm/clangd-www/
+
+### Communication channels
+
+If you have any questions or feedback, you can reach community and developers
+through one of these channels:
+
+- chat: #clangd room hosted on [LLVM's Discord
+  channel](https://discord.gg/xS7Z362).
+- user questions and feature requests can be asked in the clangd topic on [LLVM
+  Discussion Forums](https://llvm.discourse.group/c/llvm-project/clangd/34)

clang-tools-extra/docs/clangd/README.txt

@@ -0,0 +1,4 @@
+The clangd documentation lives in a separate repository.
+
+Source repo: https://github.com/llvm/clangd-www
+Public URL: https://clangd.llvm.org/