Refactor to tty_nr process field display

If no terminal name can be found, fall back to generic display method
with major and minor device numbers.

Print special value '(none)' in case both are zero.

Process.c

@@ -365,7 +365,17 @@ void Process_writeField(const Process* this, RichString* str, ProcessField field
    case TIME: Process_printTime(str, this->time); return;
    case TGID: xSnprintf(buffer, n, "%*d ", Process_pidDigits, this->tgid); break;
    case TPGID: xSnprintf(buffer, n, "%*d ", Process_pidDigits, this->tpgid); break;
-   case TTY_NR: xSnprintf(buffer, n, "%3u:%3u ", major(this->tty_nr), minor(this->tty_nr)); break;
+   case TTY_NR: {
+      unsigned int major = major(this->tty_nr);
+      unsigned int minor = minor(this->tty_nr);
+      if (major == 0 && minor == 0) {
+         attr = CRT_colors[PROCESS_SHADOW];
+         xSnprintf(buffer, n, "(none)   ");
+      } else {
+         xSnprintf(buffer, n, "%3u:%3u  ", major, minor);
+      }
+      break;
+   }
    case USER: {
       if (Process_getuid != this->st_uid)
          attr = CRT_colors[PROCESS_SHADOW];

linux/LinuxProcess.c

@@ -607,15 +607,14 @@ static void LinuxProcess_writeField(const Process* this, RichString* str, Proces
    int attr = CRT_colors[DEFAULT_COLOR];
    size_t n = sizeof(buffer) - 1;
    switch (field) {
-   case TTY_NR: {
+   case TTY_NR:
       if (lp->ttyDevice) {
-         xSnprintf(buffer, n, "%-9s", lp->ttyDevice + 5 /* skip "/dev/" */);
-      } else {
-         attr = CRT_colors[PROCESS_SHADOW];
-         xSnprintf(buffer, n, "?        ");
+         xSnprintf(buffer, n, "%-8s ", lp->ttyDevice + 5 /* skip "/dev/" */);
+         break;
       }
-      break;
-   }
+
+      Process_writeField(this, str, field);
+      return;
    case CMINFLT: Process_colorNumber(str, lp->cminflt, coloring); return;
    case CMAJFLT: Process_colorNumber(str, lp->cmajflt, coloring); return;
    case M_DRS: Process_humanNumber(str, lp->m_drs * pageSizeKB, coloring); return;