fix: magic-move regex to handle trailing whitespace (#2358)

Co-authored-by: kermanx <63178754+kermanx@users.noreply.github.com>
Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: _Kerman <kermanx@qq.com>

Author: Copilot

packages/slidev/node/syntax/transform/magic-move.ts

@@ -4,7 +4,8 @@ import { codeToKeyedTokens } from 'shiki-magic-move/core'
 import { reCodeBlock } from './code-wrapper'
 import { normalizeRangeStr } from './utils'
 
-const reMagicMoveBlock = /^````(?:md|markdown) magic-move(?: *\[([^\]]*)\])?(?: *(\{[^}]*\}))? *([^ \n]*)\n([\s\S]+?)^````$/gm
+// eslint-disable-next-line regexp/no-super-linear-backtracking
+const reMagicMoveBlock = /^````(?:md|markdown) magic-move(?: *\[([^\]]*)\])?(?: *(\{[^}]*\}))? *([^\n]*)\n([\s\S]+?)^````\s*?$/gm
 
 function parseLineNumbersOption(options: string) {
   return /lines: *true/.test(options) ? true : /lines: *false/.test(options) ? false : undefined