Don't show internal server error on rename

Doesn't quite work due to https://github.com/microsoft/vscode-languageserver-node/issues/730

Note that this intentionally removes `impl std::Error for RenameError`
-- we nether want to blindly bubble the rename error.

crates/rust-analyzer/src/to_proto.rs

@@ -8,7 +8,8 @@ use ide::{
     Assist, AssistKind, CallInfo, CompletionItem, CompletionItemKind, Documentation, FileId,
     FileRange, FileSystemEdit, Fold, FoldKind, Highlight, HlMod, HlPunct, HlRange, HlTag, Indel,
     InlayHint, InlayKind, InsertTextFormat, LineIndex, Markup, NavigationTarget, ReferenceAccess,
-    Runnable, Severity, SourceChange, SourceFileEdit, SymbolKind, TextEdit, TextRange, TextSize,
+    RenameError, Runnable, Severity, SourceChange, SourceFileEdit, SymbolKind, TextEdit, TextRange,
+    TextSize,
 };
 use itertools::Itertools;
 
@@ -855,6 +856,10 @@ pub(crate) fn markup_content(markup: Markup) -> lsp_types::MarkupContent {
     lsp_types::MarkupContent { kind: lsp_types::MarkupKind::Markdown, value }
 }
 
+pub(crate) fn rename_error(err: RenameError) -> crate::LspError {
+    crate::LspError { code: lsp_server::ErrorCode::InvalidParams as i32, message: err.to_string() }
+}
+
 #[cfg(test)]
 mod tests {
     use ide::Analysis;