vim-patch:8.0.1549: various small problems in test files

Problem:    Various small problems in test files.
Solution:   Include small changes.
5d7ead3bc8

src/nvim/testdir/shared.vim

@@ -134,6 +134,8 @@ func s:kill_server(cmd)
 endfunc
 
 " Wait for up to a second for "expr" to become true.
+" A second argument can be used to specify a different timeout in msec.
+"
 " Return time slept in milliseconds.  With the +reltime feature this can be
 " more than the actual waiting time.  Without +reltime it can also be less.
 func WaitFor(expr, ...)

src/nvim/testdir/test_vimscript.vim

@@ -1,4 +1,4 @@
-" Test various aspects of the Vim language.
+" Test various aspects of the Vim script language.
 " Most of this was formerly in test49.
 
 "-------------------------------------------------------------------------------