model : Maincoder-1B support (#18534)

* Add Maincoder model support

* Removed SPM model vocabulary setting and MOE related GGUF parameters
Removed trailing spaces from maincoder.cpp

* removed set_vocab

* added new line

* Fix formatting

* Add a new line for PEP8

convert_hf_to_gguf.py

@@ -6415,6 +6415,17 @@ class ARwkv7Model(Rwkv7Model):
         self.gguf_writer.add_head_count(0)
 
 
+@ModelBase.register("MaincoderForCausalLM")
+class MaincoderModel(TextModel):
+    model_arch = gguf.MODEL_ARCH.MAINCODER
+
+    def set_gguf_parameters(self):
+        super().set_gguf_parameters()
+
+        if (head_dim := self.hparams.get("head_dim")) is not None:
+            self.gguf_writer.add_rope_dimension_count(head_dim)
+
+
 @ModelBase.register("MambaForCausalLM", "MambaLMHeadModel", "FalconMambaForCausalLM")
 class MambaModel(TextModel):
     model_arch = gguf.MODEL_ARCH.MAMBA