How to avoid newline insertion / reindentation by sgml-tag (C-c C-t) in html-mode

[David Madore]

Dear group,

I only recently upgraded from Emacs 24.5 to 25.1.  One of the changes 
which is causing me considerable pain is that the html-mode (which I use 
a lot to edit XHTML files) now tries to perform some kind of 
reindentation whenever a tag is inserted by the sgml-tag (C-c C-t) 
function.  In particular, a line break appears to be inserted whenever 
there is a following closed tag.

I would like no such reindentation to occur.  For example, if I type 
"C-c C-t em" between <p> and </p> (say), I would just like for "<em>" to 
be inserted before the point and "</em>" after, with no changes to 
indentation or anything else, and certainly no extra newline character.

I tried understanding sgml-mode.el but it is way beyond my knowledge of 
Emacs Lisp; and I don't see in the diff between the 24.5 and 25.1 
versions anything pertaining to identation that would explain the 
difference.  I even tried using the 24.5 version of sgml-mode.el but it 
did not revert to the previous behavior (so I assume the difference 
comes from somewhere else but I don't even know where to start looking).

Does anybody know how I can revert to the previous behaviour and avoid 
the spurious insertion of newlines by the sgml-tag function?

Failing that, can anybody suggest some way to get help on this 
particular issue?

Many thanks in advance for any advice,

--
     David A. Madore
WWW: http://www.madore.org/~david/