[clang-tools-extra] [clangd] Add dynamic plugins support (PR #226995)

[Aleksandr Platonov via cfe-commits]

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@@ -0,0 +1,14 @@
+// REQUIRES: plugins
+// RUN: clangd --help | FileCheck --check-prefix=CHECK-HELP %s
+// CHECK-HELP: --load=<pluginfilename> - Load the specified plugin
+
+// RUN: cp %s %t.cpp
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ArcsinX wrote:

Theoretically we can use just `%s` here, but  we need to pass this file as an input to clangd in check mode via `clangd -check=file_is_here` (the next line), but the extension of this file is `.test` and it can be just skipped. So, here we copy this file to `....cpp` to ensure it will be processed as a C/C++ file.

https://github.com/llvm/llvm-project/pull/226995