setIncrementalBuild(isIncremental) {
		this.isIncremental = !!isIncremental;

		if (this.watchManager) {
			this.watchManager.incremental = !!isIncremental;
		}
		if (this.writer) {
			this.writer.setIncrementalBuild(this.isIncremental);
		}
	}
Sets the incremental build mode.

@param {boolean} isIncremental - Shall Eleventy run in incremental build mode and only write the files that trigger watch updates