README.md: Make a few polishing changes (jsc#PED-5021)
    
    * Move @suse.com address at the front of SUSE email domains, as that is
      the one that should be normally used for contributions, according to
      the current SUSE Open Source Policy.
    * Avoid repeatedly using "please" in two consecutive sentences.
    * Fix a typo in section "Patch sorting": "commit" -> "commits".
    * Prefix relative commands in section "Config option changes" with "./"
      even if they are from a subdirectory, for consistency with the rest of
      the document.
    * Turn "Related information" into a proper list.