vim-patch:bfb9f5c: runtime(doc): Rename NoDefaultCurrentDirectoryInExePath tag (#36921)

- Add leading "$" to match other environment variable tags.
- Clarify :help $NoDefaultCurrentDirectoryInExePath.

closes: vim/vim#18895

bfb9f5c40e

Co-authored-by: Doug Kearns <dougkearns@gmail.com>

src/nvim/eval.lua

@@ -2161,13 +2161,14 @@ M.funcs = {
 
       On MS-Windows an executable in the same directory as the Vim
       executable is always found (it's added to $PATH at |startup|).
-      			*NoDefaultCurrentDirectoryInExePath*
+      			*$NoDefaultCurrentDirectoryInExePath*
       On MS-Windows when using cmd.exe as 'shell' an executable in
       Vim's current working directory is also normally found, which
       can be disabled by setting the
       `$NoDefaultCurrentDirectoryInExePath` environment variable.
-      This is always done when executing external commands using
-      e.g. |:!|, |:make|, |system()| for security reasons.
+      This variable is always set by Vim when executing external
+      commands (e.g., via |:!|, |:make|, or |system()|) for security
+      reasons.
 
       The result is a Number:
       	1	exists