Meta: Add .clangd config file (with project-recommended defaults)

This change also removes parts of the existing docs that explain how to
create a .clangd file with the project-recommended  defaults. (Those
docs are no longer necessary — since this change adds a .clangd file to
the repo, containing those same defaults).

.clangd

@@ -0,0 +1,6 @@
+CompileFlags:
+  CompilationDatabase: Build/ladybird
+
+Diagnostics:
+  UnusedIncludes: None
+  MissingIncludes: None

Documentation/EmacsConfiguration.md

@@ -4,20 +4,10 @@ Emacs can be configured with `lsp-mode` and `clangd` to work well.
 
 ### clangd
 
-The official clangd extension can be used for C++ comprehension. You
-can use the following `.clangd` file placed in the project root:
+The official clangd extension can be used for C++ comprehension.
 
-```yaml
-CompileFlags:
-  CompilationDatabase: Build/ladybird
-
-Diagnostics:
-  UnusedIncludes: None
-  MissingIncludes: None
-```
-
-Run cmake (`Meta/ladybird.sh run ladybird` or similar) at least once for this
-to work, as it will generate the `Build/ladybird/compile_commands.json`
+Run cmake (`Meta/ladybird.sh run ladybird` or similar) at least once for clangd
+to work, as doing so will generate the `Build/ladybird/compile_commands.json`
 that is needed by `clangd`.
 
 ### lsp-mode

Documentation/HelixConfiguration.md

@@ -1,17 +1,5 @@
 # Helix Configuration
-Helix comes with support for `clangd` and `clang-format` out of the box! However, a small bit of configuration is needed for it to work correctly with Ladybird.
-
-The following `.clangd` should be placed in the project root:
-```yaml
-CompileFlags:
-  CompilationDatabase: Build/ladybird
-
-Diagnostics:
-  UnusedIncludes: None
-  MissingIncludes: None
-```
-
-You also need to configure the clangd server to not insert headers improperly. To do this, create a `.helix/languages.toml` file in the project root:
+Helix comes with support for `clangd` and `clang-format` out of the box! However, you also need to configure the clangd server to not insert headers improperly. To do this, create a `.helix/languages.toml` file in the project root:
 ```toml
 [language-server.ladybird]
 command = "clangd"

Documentation/NvimConfiguration.md

@@ -7,17 +7,7 @@ project:
 2. With [coc.nvim](https://github.com/neoclide/coc.nvim) (from scratch, potentially out of date)
 
 For both setups, make sure you ran `./Meta/ladybird.sh run ladybird` at least 
-once. Additionally, clangd should be configured with the following (in the
-`.clangd` file at the root of the project):
-
-```yaml
-CompileFlags:
-  CompilationDatabase: Build/ladybird
-
-Diagnostics:
-  UnusedIncludes: None
-  MissingIncludes: None
-```
+once.
 
 ## With nvim-lspconfig
 

Documentation/VSCodeConfiguration.md

@@ -24,19 +24,6 @@ Clangd has the best support for modern compilers, especially if configured as no
 The official clangd extension can be used for C++ comprehension. It is recommended in general, as it is most likely to work on all platforms.
 
 clangd uses ``compile_commands.json`` files to understand the project. CMake will generate these in Build/ladybird.
-Depending on which configuration you use most, set the CompilationDatabase configuration item in the below ``.clangd`` file accordingly. It goes at the root of your checkout (``ladybird/.clangd``):
-
-```yaml
-CompileFlags:
-  CompilationDatabase: Build/ladybird
-
-Diagnostics:
-  UnusedIncludes: None
-  MissingIncludes: None
-```
-
-The UnusedIncludes and MissingIncludes flags are used to disable the [Include Cleaner](https://clangd.llvm.org/design/include-cleaner) feature of newer clangd releases.
-It can be re-enabled if you don't mind the noisy inlay hints and problems in the problem view.
 
 Run ``./Meta/ladybird.sh run ladybird`` at least once to generate the ``compile_commands.json`` file.