lsp: support rust-analyzer on helix editor (#103)

This patch allows the helix editor to correctly initialize the
rust-analyzer when opening a source file from {{project-name}}-ebpf.

To find the Cargo.toml the helix editor must be launched from
the {{project-name}}-ebpf directory or provide the workspace path
as follows:

hx -w <path to {{project-name}}-ebpf> [relative path in {{project-name}}-ebpf]

The patch was tested using helix version 23.10.

{{project-name}}-ebpf/.helix/config.toml

@@ -0,0 +1,2 @@
+[editor]
+workspace-lsp-roots = []