:cur[sor]

[elazarcoh]

What this PR does / why we need it:
Add cursors by search pattern. fixes #7152
Can add cursor at a specific location using special indicator. Currently I'm using \#.

Feature:
Consider this example: (cursor indicated by |)

def foo():
|def bar(): 
def bizbaz():
def moo():

1. :cur def (all matches)

   |def foo():
   |def bar():
   |def bizbaz():
   |def moo():

2. :cur 2 def (limit number of matches)

   def foo():
   |def bar():
   |def bizbaz():
   def moo():

3. :cur de\#f (at specified location)

   de|f foo():
   de|f bar():
   de|f bizbaz():
   de|f moo():

4. :cur \#de\#f (multiple cursor)

   |de|f foo():
   |de|f bar():
   |de|f bizbaz():
   |de|f moo():

5. :cur def \w+\# (using regex)

   def foo|():
   def bar|():
   def bizbaz|():
   def moo|():

6. vj :'<,'>cur def (in selection range)

   def foo():
   |def bar():
   |def bizbaz():
   def moo():

Edit:
Added cursor from current word/selection in case of empty pattern

7. :cur (select current word as pattern)

   |def foo():
   |def bar():
   |def bizbaz():
   |def moo():

8. :cur 2 (select current word as pattern, with limit)

   def foo():
   |def bar():
   |def bizbaz():
   def moo():

9. lvll:'<,'>cur 2 (the selection is used for pattern, similar to * in visual mode)

   def foo():
   d|ef bar():
   d|ef bizbaz():
   def moo():

Which issue(s) this PR fixes

Special notes for your reviewer:

[elazarcoh]

Added new feature: cursors from current word/selection, when not giving a pattern to the command.
examples is PR description.