Trim trailing whitespace

Commands used to search and replace:

    $ git grep -Ilz '[[:blank:]]$' |
      xargs -0 -I '{}' sh -c "printf '%s\n' \"\$(sed -E \
        's/[[:blank:]]+$//' '{}')\" >'{}'"

This fixes all of the "trailing whitespace" errors raised by git:

    $ git diff --check 4b825dc642cb6eb9a060e54bf8d69288fbee4904..HEAD |
      grep '^[^+]' | cut -f 3 -d : | LC_ALL=C sort | uniq -c
         72  space before tab in indent.
          4  trailing whitespace.

.github/ISSUE_TEMPLATE/bug_report.md

@@ -81,7 +81,7 @@ output goes here
 <details>
 <summary>Output of <code>LC_ALL=C firejail --debug /path/to/program</code></summary>
 <p>
-  
+
 <!-- If the output is too long to embed it into the comment,
      create a secret gist at https://gist.github.com/ and link it here. -->
 

.github/pull_request_template.md

@@ -1,9 +1,9 @@
 If your PR isn't about profiles or you have no idea how to do one of these, skip the following and go ahead with this PR.
 
 If you submit a PR for new profiles or changing profiles, please do the following:
- - The ordering of options follow the rules described in [/usr/share/doc/firejail/profile.template](https://github.com/netblue30/firejail/blob/master/etc/templates/profile.template).  
+ - The ordering of options follow the rules described in [/usr/share/doc/firejail/profile.template](https://github.com/netblue30/firejail/blob/master/etc/templates/profile.template).
    > Hint: The profile-template is very new. If you install firejail with your package manager, it may be missing. In order to follow the latest rules, it is recommended to use the template from the repository.
- - Order the arguments of options alphabetically. You can easily do this with [sort.py](https://github.com/netblue30/firejail/tree/master/contrib/sort.py).  
+ - Order the arguments of options alphabetically. You can easily do this with [sort.py](https://github.com/netblue30/firejail/tree/master/contrib/sort.py).
  The path to it depends on your distro:
 
    | Distro | Path |

etc/profile-m-z/rpcs3.profile

@@ -2,7 +2,7 @@
 # Description: RPCS3 emulator
 # This file is overwritten after every install/update
 # Persistent local customizations
-include rpcs3.local 
+include rpcs3.local
 # Persistent global definitions
 include globals.local