Reasoning: Add template with <think> without newlines

Fixes #4932

default/content/index.json

@@ -638,5 +638,9 @@
     {
         "filename": "presets/reasoning/OpenAI Harmony.json",
         "type": "reasoning"
+    },
+    {
+        "filename": "presets/reasoning/Think XML.json",
+        "type": "reasoning"
     }
 ]

default/content/presets/reasoning/Think XML.json

@@ -0,0 +1,6 @@
+{
+    "name": "Think XML",
+    "prefix": "<think>",
+    "suffix": "</think>",
+    "separator": "\n"
+}

public/scripts/reasoning.js

@@ -31,7 +31,7 @@ import { copyText, escapeRegex, isFalseBoolean, isTrueBoolean, setDatasetPropert
  */
 export const reasoning_templates = [];
 
-export const DEFAULT_REASONING_TEMPLATE = 'DeepSeek';
+export const DEFAULT_REASONING_TEMPLATE = 'Think XML';
 
 /**
  * @type {Record<string, JQuery<HTMLElement>>} List of UI elements for reasoning settings