fix: avoid toggling empty links, fix bug where some functions don't get called in template

[jeffmm]

Context

Hi @lervag, I really like your plugin so far! I made a few small changes locally and thought I'd share them:

• I noticed an annoying error if I accidentally hit Return in normal mode when my cursor was on a blank line.
• I had a problem with consecutive user-defined functions not being called in my wiki template

Changes

• If there is no text under the cursor, exit early from wiki#link#follow(don't attempt to toggle an empty link)
• make the search for user-defined template functions less aggressive, since after the insertion of the result of the function call the length of the variable l:lines changes, and l:c2 can extend beyond the beginning of the next curly-braces defining another custom function.

[lervag]

Hi @lervag, I really like your plugin so far!

Thanks, glad you like it!

I made a few small changes locally and thought I'd share them:

I'm quite impressed that you managed to fix the errors; well done! Especially the second one is quite intricate, and I would not be surprised if I would have spent some time pinpointing and fixing it myself.