PR openxla#8306: Add instructions to generate compile_commands.json

Imported from GitHub PR openxla#8306

Copybara import of the project:

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ef2ff97 by Andrey Portnoy <aportnoy@nvidia.com>:

Add instructions to generate compile_commands.json

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21916c7 by Andrey Portnoy <aportnoy@nvidia.com>:

Remove defensive phrasing from LSP instructions

Merging this change closes openxla#8306

COPYBARA_INTEGRATE_REVIEW=openxla#8306 from andportnoy:aportnoy/compile-commands-documentation 21916c7
PiperOrigin-RevId: 598964502

docs/index.md

@@ -50,3 +50,4 @@ then read [Code reviews](code_reviews.md).
 -   [Operation semantics](operation_semantics.md)
 -   [Shapes and layout](shapes.md)
 -   [Tiled layout](tiled_layout.md)
+-   [Setting up LSP with clangd](lsp.md)

docs/lsp.md

@@ -0,0 +1,20 @@
+# Setting up LSP with clangd
+
+## Background
+
+Editors such as Emacs, Vim, or VS Code support features like code navigation,
+code completion, inline compiler error messages, and others, through
+[LSP](https://en.wikipedia.org/wiki/Language_Server_Protocol), the Language
+Server Protocol. A common language server with LSP support is
+[clangd](https://clangd.llvm.org), which relies on the presence of
+`compile_commands.json`, a JSON file with a record of the compile commands for
+each file in a project.
+
+## How do I generate `compile_commands.json` for XLA source code?
+
+Use the
+[build_tools/lint/generate_compile_commands.py](https://github.com/openxla/xla/blob/main/build_tools/lint/generate_compile_commands.py)
+script. The following invocation from XLA repo root generates a
+`compile_commands.json` file in place: `bash bazel aquery "mnemonic(CppCompile,
+//xla/...)" --output=jsonproto | \ python3
+build_tools/lint/generate_compile_commands.py`