cpu : add FLOOR, CEIL, ROUND and TRUNC unary operators (#16083)

* CPU: Add support for FLOOR,CEIL,ROUND and TRUNC unary operators

- Added the operators to unary op enum
- Implemented API functions
- Implemented forward and unary-op logic in CPU backend
- Updated ggml_get_n_tasks
- Updated operators names array and static_assert
- Updated docs and enabled automatic tests

* docs: add documentation for ggml_trunc and ggml_trunc_inplace in ggml.h

* chore: remove trailing whitespace from ggml.h

* Remove unresolved merge markers

* Apply review suggestions: cleanup formatting, enum order and leftover artifacts

* Regenerate ops.md using create_ops_docs.py

ggml/src/ggml-cpu/ggml-cpu.c

@@ -2184,6 +2184,10 @@ static int ggml_get_n_tasks(struct ggml_tensor * node, int n_threads) {
                 case GGML_UNARY_OP_HARDSWISH:
                 case GGML_UNARY_OP_HARDSIGMOID:
                 case GGML_UNARY_OP_EXP:
+                case GGML_UNARY_OP_FLOOR:
+                case GGML_UNARY_OP_CEIL:
+                case GGML_UNARY_OP_ROUND:
+                case GGML_UNARY_OP_TRUNC:
                     {
                         n_tasks = 1;
                     } break;