docs : Minor cleanups (#19252)

* Update old URLs to github.com/ggml-org/

* Bump copyrights

src/models/deepseek2.cpp

@@ -14,7 +14,7 @@ llm_build_deepseek2::llm_build_deepseek2(const llama_model & model, const llm_gr
     const uint32_t kv_lora_rank = hparams.n_lora_kv;
 
     // We have to pre-scale kq_scale and attn_factor to make the YaRN RoPE work correctly.
-    // See https://github.com/ggerganov/llama.cpp/discussions/7416 for detailed explanation.
+    // See https://github.com/ggml-org/llama.cpp/discussions/7416 for detailed explanation.
     // And also: https://github.com/ggml-org/llama.cpp/pull/17945 [TAG_DEEPSEEK2_YARN_LOG_MUL_FIX]
 
     // first cancel the adjustment from llama_hparams::yarn_attn_factor_adjust to get the original attn_factor