I'm not sure I was recommending it exactly, just describing what I use.
I like the idea of adding the vim info to the PHP files, though, and have just added something to that bug (and the main library files) about it.
Tags are easy to generate with Unix on individual installations ... just go the main Moodle directory and run "ctags -R" (My file is 300K which is a bit large to include in the distribution ... unless there are some Windows+vi developers who would find it useful.)
In .vimrc add a line to set tags to search local tags, then the global tag file, like:
set tags=./tags,/web/moodle/tags
For those who've never used tags before, it's a very fast way of jumping around code. You place the cursor over a function call and hit Ctrl-] to jump directly to that function. Ctrl-T brings you back again. You can jump several steps away and return one step at a time. The tags file is just an index to keep things fast.