extensions/git/src/git.ts/Git/mergeFile
class Git:	async mergeFile(options: { input1Path: string; input2Path: string; basePath: string; diff3?: boolean }): Promise<string> {
		const args = ['merge-file', '-p', options.input1Path, options.basePath, options.input2Path];
		if (options.diff3) {
			args.push('--diff3');
		} else {
			args.push('--no-diff3');
		}

		try {
			const result = await this.exec('', args);
			return result.stdout;
		} catch (err) {
			if (typeof err.stdout === 'string') {
				// The merge had conflicts, stdout still contains the merged result (with conflict markers)
				return err.stdout;
			} else {
				throw err;
			}
		}
	}