Auto merge of rust-lang#12951 - jonas-schievink:doc-cli-stability, r=Veykril

internal: Document CLI flag stability

Author: bors

crates/rust-analyzer/src/cli/flags.rs

@@ -10,6 +10,10 @@ xflags::xflags! {
     src "./src/cli/flags.rs"
 
     /// LSP server for the Rust programming language.
+    ///
+    /// Subcommands and their flags do not provide any stability guarantees and may be removed or
+    /// changed without notice. Top-level flags that are not are marked as [Unstable] provide
+    /// backwards-compatibility and may be relied on.
     cmd rust-analyzer {
         /// Verbosity level, can be repeated multiple times.
         repeated -v, --verbose
@@ -21,7 +25,7 @@ xflags::xflags! {
         /// Flush log records to the file immediately.
         optional --no-log-buffering
 
-        /// Wait until a debugger is attached to (requires debug build).
+        /// [Unstable] Wait until a debugger is attached to (requires debug build).
         optional --wait-dbg
 
         default cmd lsp-server {