refactor(options): reduce `findoption()` usage

Problem: Many places in the code use `findoption()` to access an option using its name, even if the option index is available. This is very slow because it requires looping through the options array over and over.

Solution: Use option index instead of name wherever possible. Also introduce an `OptIndex` enum which contains the index for every option as enum constants, this eliminates the need to pass static option names as strings.

1 files changed, 2 insertions, 2 deletions

diff --git a/src/nvim/autocmd.c b/src/nvim/autocmd.c
index 46a08c5706..72b0852d8d 100644
--- a/src/nvim/autocmd.c
+++ b/src/nvim/autocmd.c
@@ -704,7 +704,7 @@ char *au_event_disable(char *what)
   } else {
     STRCAT(new_ei, what);
   }
-  set_string_option_direct("ei", -1, new_ei, OPT_FREE, SID_NONE);
+  set_string_option_direct(kOptEventignore, new_ei, OPT_FREE, SID_NONE);
   xfree(new_ei);
   return save_ei;
 }
@@ -712,7 +712,7 @@ char *au_event_disable(char *what)
 void au_event_restore(char *old_ei)
 {
   if (old_ei != NULL) {
-    set_string_option_direct("ei", -1, old_ei, OPT_FREE, SID_NONE);
+    set_string_option_direct(kOptEventignore, old_ei, OPT_FREE, SID_NONE);
     xfree(old_ei);
   }
 }