docs(deepseek): use TOML literal strings for JSON configs

Switched from triple-quoted multi-line strings to single-line
literal strings ('...'): no need for newlines or escaping of the
inner '"' characters.

    "--speculative-config", '{"method":"mtp",...}',

recipes/deepseek-v4-flash/recipe.toml

@@ -19,14 +19,12 @@ args = [
     "--max-num-batched-tokens", "8192",
     "--gpu-memory-utilization", "0.82",
     "--enable-prefix-caching",
-    "--speculative-config", """
-{"method":"mtp","num_speculative_tokens":2}""",
+    "--speculative-config", '{"method":"mtp","num_speculative_tokens":2}',
     "--tokenizer-mode", "deepseek_v4",
     "--tool-call-parser", "deepseek_v4",
     "--enable-auto-tool-choice",
     "--reasoning-parser", "deepseek_v4",
-    "--reasoning-config", """
-{"reasoning_parser":"deepseek_v4","reasoning_start_str":"","reasoning_end_str":""}""",
+    "--reasoning-config", '{"reasoning_parser":"deepseek_v4","reasoning_start_str":"","reasoning_end_str":""}',
     "--default-chat-template-kwargs.thinking", "true",
     "--default-chat-template-kwargs.reasoning_effort", "high",
     "--enable-flashinfer-autotune",