fix: <script> without src is not delayed like <script src="..." defer>

[shenlebantongying]

Fix issue caused by defer for external scripts.

goldendict-ng/src/dict/mdx.cc

Lines 978 to 981 in ad19263

	//add defer to script tag
	if ( linkType.compare( "script" ) == 0 ) {
	newText = newText + " defer ";
	}

The defer will delay the execution of external script to a time between "Page loaded" and DOMContentLoaded.

I don't put much thought yet, but this will immediately fix #1984

Also don't want to use jQuery because it creates a barrier on approaching the HTML standard.

[shenlebantongying]

Alternative fix of http://forum.freemdict.com/t/topic/11495/3575 @atauzki

The defer was to fix #1379

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[shenlebantongying]

Not sure if this is a good thing to do, but let's merge and see.

[atauzki]

works.
Actually I have removed this <script> tag to js file and repacked them yesterday.