docs: misc. typos pt2

Remainder of typos found using `codespell -q 3 --skip="./shared,./src/systemd,*.po" -I ../NetworkManager-word-whitelist.txt` whereby whitelist consists of:
 ```
ans
busses
cace
cna
conexant
crasher
iff
liftime
creat
nd
sav
technik
uint
```

https://github.com/NetworkManager/NetworkManager/pull/205

libnm/generate-plugin-docs.pl

@@ -60,7 +60,7 @@ open $fo, '>', $output or die "Can't open $output: $!";
 # write XML header
 write_header();
 
-# write generated documenation for each setting
+# write generated documentation for each setting
 foreach my $c_file (@source_files) {
   my $setting_name = get_setting_name($c_file);
   if ($setting_name) {