shrink-path: added glob and quote options (#7694)

* Added -g option to shrink-path plugin.

The new optins adds an asterix to the uniquely shortened name, such
that, if copy'n'pasted, zsh globbing will expand to the full path name
of the shortened path:

shrink-path -g:
"/net/software/modules/modulefiles" -> "/n*/s*/modules/m*"

shrink-path -l -g:
"/net/software/modules/modulefiles" -> "/n*/s*/modules/modulefiles"

* Updated also the README file with the new -g option.

* shrink-path: improved handling of special cases

This commits improves the handling of special cases in path strings:

- handling of white space in path names
- handling of single-letter path names

* Update plugins/shrink-path/README.md

Co-Authored-By: Jacob Tomaw <jacob.tomaw@gmail.com>

* Fix typo "Asterix" and replace with "asterisk"

* Add optional quoting support to shrink_path

Co-authored-by: Jacob Tomaw <jacob.tomaw@gmail.com>

plugins/shrink-path/README.md

@@ -7,21 +7,26 @@ For this directory tree:
 ```
     /home/
       me/
-        foo/
+        f o o/     # The prefix f is ambiguous between "f o o" and "f i g".
           bar/
             quux/
           biz/     # The prefix b is ambiguous between bar and biz.
+        f i g/
+          baz/
 ```
 here are the results of calling `shrink_path <option> /home/me/foo/bar/quux`:
 ```
     Option        Result
-    <none>        /h/m/f/ba/q
-    -l|--last     /h/m/f/ba/quux
+    <none>        /h/m/f o/ba/q
+    -l|--last     /h/m/f o/ba/q
     -s|--short    /h/m/f/b/q
-    -t|--tilde    ~/f/ba/q
+    -t|--tilde    ~/f o/ba/q
     -f|--fish     ~/f/b/quux
-    -3            /hom/me/foo/bar/quu
-    -e '$' -3     /ho$/me/foo/bar/qu$
+    -g|--glob     /h*/m*/f o*/ba*/q*
+    -3            /hom/me/f o/bar/quu
+    -e '$' -3     /hom$/me/f o$/bar/quu$
+    -q            /h/m/f\ o/ba/q
+    -g -q         /h*/m*/f\ o*/ba*/q*
 ```
 
 
@@ -39,6 +44,7 @@ The following options are available:
 
 ```
     -f, --fish       fish simulation, equivalent to -l -s -t.
+    -g, --glob       Add asterisk to allow globbing of shrunk path (equivalent to -e "*")
     -l, --last       Print the last directory's full name.
     -s, --short      Truncate directory names to the number of characters given by -. Without
                      -s, names are truncated without making them ambiguous.
@@ -47,6 +53,7 @@ The following options are available:
     -#               Truncate each directly to at least this many characters inclusive of the
                      ellipsis character(s) (defaulting to 1).
     -e SYMBOL        Postfix symbol(s) to indicate that a directory name had been truncated.
+    -q, --quote      Quote special characters in the shrunk path
 ```
 
 The long options can also be set via zstyle, like