At the top of dired buffer, I have a line as follows,

  /tmp: (41 GiB available)

and I want to move the cursor to select the path `/tmp'.

The problem is isearch-forward for the next `:' from the position at the
left most occurrence of `/' overshoots to the end of line.

Steps to demonstrate,
 1. start,                                     emacs -Q
 2. goto directory,                            C-x d /tmp/
 3. goto beginning of dired buffer,            ESC <
    i.  move cursor to left most `/' position
    ii. activate mark                          C-SPC
 4. search forward to match `:',               C-s :

Intended unavailable effect, to move the cursor to the first occurence of `:'.

Unintended actual effect, the cursor moves to the end of line.