Support ~, - and & keyboard shortcuts at the bookmark prompt.

In nav-as-you-type mode only control keys are understood when filter is enabled.
We need some way to quicly jump HOME, last visited dir or start dir.

README.md

@@ -340,6 +340,8 @@ Set environment variable `NNN_BMS` as a string of `key:location` pairs (max 10)
 
     export NNN_BMS='doc:~/Documents;u:/home/user/Cam Uploads;D:~/Downloads/'
 
+The bookmark prompt also understands the <kbd>~</kbd> (HOME), <kbd>-</kbd> (last visited directory) and <kbd>&</kbd> (start directory) shortcuts.
+
 #### use cd .....
 
 To jump to the n<sup>th</sup> level parent, with PWD at level 0, use `n + 1` dots. For example, to jump to the 6<th> parent of the current directory, use 7 dots. If the number of dots would take you *beyond* `/` (which isn't possible), you'll be placed at `/`.

nnn.1

@@ -220,6 +220,7 @@ when dealing with the !, e and p commands respectively.
 .Bd -literal
     export NNN_BMS='doc:~/Documents;u:/home/user/Cam Uploads;D:~/Downloads/'
 .Ed
+The bookmark prompt also understands the \fI~\fR (HOME), \fI-\fR (last visited directory) and \fI&\fR shortcuts.
 .Pp
 \fBNNN_USE_EDITOR:\fR use EDITOR (preferably CLI, fallback vi) to handle text
 files.

nnn.c

@@ -2726,9 +2726,15 @@ nochange:
 			printprompt("key: ");
 			tmp = readinput();
 			clearprompt();
-			if (tmp == NULL)
+			if (tmp == NULL || tmp[0] == '\0')
 				break;
 
+			/* Interpret ~, - and & keys */
+			if ((tmp[1] == '\0') && (tmp[0] == '~' || tmp[0] == '-' || tmp[0] == '&')) {
+				presel = tmp[0];
+				goto begin;
+			}
+
 			if (get_bm_loc(tmp, newpath) == NULL) {
 				printmsg(messages[STR_INVBM_ID]);
 				goto nochange;