* Fix many broken links
Note that contrary to what docgen.rst currently says, the ids have
to match exactly or else most web browsers will not jump to the
intended symbol.
* Prefer relative links for Nim documentation
This is more friendly to those browsing the documentation without
a network connection. The nim-doc package in Debian allows this,
for example.
Also, the domain name being used was not consistent. It could have
been either nim-lang.org or nim-lang.github.io, and those reading
the stable docs could have found themselves suddenly reading the
devel docs instead.
* koch.rst: remove link to nonexistent section
* manual.rst: remove unintended link
cast[T](0) is interpreted as a link to id 0 with text T, so escape
the opening parentheses to display the intended output.
* asyncstreams: replace unintended link with emphasis
* Fix word wrapping
b03de8a4d9