fix: Explicit match-string caught by pre-commit GHA

https://google.github.io/styleguide/vimscriptguide.xml?showone=Matching_Strings#Matching_Strings

Signed-off-by: Julian Orchard <[email protected]>

Author: julianorchard

plugin/other.vim

@@ -1,6 +1,6 @@
 " https://vim.fandom.com/wiki/Increasing_or_decreasing_numbers
 function! AddSubtract(char)
-  let pattern = &nrformats =~ 'alpha' ? '[[:alpha:][:digit:]]' : '[[:digit:]]'
+  let pattern = &nrformats =~# 'alpha' ? '[[:alpha:][:digit:]]' : '[[:digit:]]'
   call search(pattern, 'cw')
   execute 'norm! ' . v:count1 . a:char
 endfunction