boost regex tolerates non-escaped special characters, and escaped
non-special characters. Standardize on stricter syntax, where
special characters must be escaped, and non-special characters must
not.
Sometimes the implementation of `man` will display errors, e.g.
```
<standard input>:4808: warning [p 54, 13.2i]: can't break line
```
Those errors are harmless but are still reported on the debug buffer,
so we hide them by redirecting the standard error stream to /dev/null.
When using the `man` filetype to make use of the text highlighters
of the `man.kak` script, the documentation pages inherit from the
window resizing hooks that won't work on `doc` buffers.
Fixes#1591
When used just after grepping, grep-next-match ended up jumping to
the second match, as `0g` is the same as `g`.
The fix itself is pretty ugly, a better one might be to distinguish
the `0` count from no count given, so that `0g` could fail with
"no such line" or similar.
Looking up the man page for `index` was failing on systems using
GNU/coreutils. The `:man` command matched whatever page it was given with
the `expr` utility. This tool behaves as expected when it follows strictly
the POSIX standard but the GNU implementation introduces additional commands
(including `index`), about which the standard states:
```
The use of string arguments length, substr, index, or match produces unspecified results.
```
As a result, parsing the man page number is now implemented with pure
shell expansions, to avoid triggering an undefined behavior when the topic
searched is one of the keywords above.
The previous implementation used to replace the contents of the buffer with
whatever the `formatcmd` was returning, regardless of the exit code of the
command, which led to the buffer being wiped out on error.
This commit does the formatting in a temporary file, and only replaces the
current buffer with the contents of the -formatted- temporary file if the
`formatcmd` returned successfully.
Fixes#1357
These are less useful with more static words, and they are
woefully incomplete: no support -docstring for map, set
uses the variable face, but there is no corresponding
highlighter for decl or %opt{..}.
