iss #809 normalize text works only in img tag

[asmsuechan]

context

I change normalizeTextLinkworks in only img tags.

before

The entities encoded even if they're not links.

%A0
%AB

ref: #809

after

%00
%AA

![img](C:\Users\asmsuechan\images\aaaa.png)

For tests

• An image link is inserted properly on windows
• %AA is rendered as %AA not �

refs

#728
#809