[yuyi98]

This PR fix variable name starts with print (fix #13981).

• Fix variable name starts with print.
• Add test.

PS D:\Vlang\v> v
 ____    ____
 \   \  /   /  |  Welcome to the V REPL (for help with V itself, type  exit , then run  v help ).
  \   \/   /   |  Note: the REPL is highly experimental. For best V experience, use a text editor,
   \      /    |  save your code in a  main.v  file and execute:  v run main.v
    \    /     |  V 0.4.6 a67bfeb . Use  list  to see the accumulated program so far.
     \__/      |  Use Ctrl-C or  exit  to exit, or  help  to see other available commands.

>>> a_variable := 'yessir'
>>> a_variable
yessir
>>> printme := 'ohno'
>>> printme
ohno
>>>