bug#26569: Parindent doesn't work according to description

[npostavs]

Saideep Bhosle <saideep@outlook.com> writes:

> Parindent (paragraph-indent-text-mode) doesn't work as described in help.
> After starting a paragraph with spaces and adding a newline (return) after
> the first line removes the spaces added at the beginning.

Yeah, this can be avoided by turning off electric-indent-mode.

> Also, cannot start a new paragraph with tab in Parindent.

It's because the indent-line-function is set to indent-to-left-margin.
Doing C-q TAB works.

Setting indent-line-function to a smarter function would fix this and
the newline problem.

> M-q mushes all paragraphs not separated by blank lines together.

I'm not able to reproduce this problem though.  As long the paragraphs
start with whitespace M-q doesn't combine them, as documented.  For
example, with the following buffer contents, pressing M-q doesn't change
the buffer:

   xxx xxxxxxxx xxxxx xxxxxx xxxxx xxx xxxxx xxx xxxxxxx xxx xxx xxx
xx xxxx x
   xxxx xxx xxxx xx xx xx xxxxxxx xxxx xxxxxxx xxx xxx xxx xx xxxx
xxxxx xx