fix: Lean language server consuming excessive memory (#11683)

The Lean process, spawned by the language server, might use excessive
memory in certain situation, causing the entire system to freeze. See:

   https://github.com/leanprover/lean4/issues/5321

The language server accepts a CLI flag for limiting memory use. I set
it to 1024MB, which might be a bit arbitrary, but definitly prevents
the system from crashing.

languages.toml

@@ -49,7 +49,7 @@ jsonnet-language-server = { command = "jsonnet-language-server", args= ["-t", "-
 julia = { command = "julia", timeout = 60, args = [ "--startup-file=no", "--history-file=no", "--quiet", "-e", "using LanguageServer; runserver()", ] }
 koka = { command = "koka", args = ["--language-server", "--lsstdio"] }
 kotlin-language-server = { command = "kotlin-language-server" }
-lean = { command = "lean", args = [ "--server" ] }
+lean = { command = "lean", args = [ "--server", "--memory=1024" ] }
 ltex-ls = { command = "ltex-ls" }
 markdoc-ls = { command = "markdoc-ls", args = ["--stdio"] }
 markdown-oxide = { command = "markdown-oxide" }