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, 3 insertions, 3 deletions

diff --git a/src/nvim/terminal.c b/src/nvim/terminal.c
index fda6aa41e8..af9693c4b0 100644
--- a/src/nvim/terminal.c
+++ b/src/nvim/terminal.c
@@ -233,7 +233,7 @@ void terminal_open(Terminal **termpp, buf_T *buf, TerminalOptions opts)
   aucmd_prepbuf(&aco, buf);
 
   refresh_screen(rv, buf);
-  set_option_value("buftype", STATIC_CSTR_AS_OPTVAL("terminal"), OPT_LOCAL);
+  set_option_value(kOptBuftype, STATIC_CSTR_AS_OPTVAL("terminal"), OPT_LOCAL);
 
   // Default settings for terminal buffers
   buf->b_p_ma = false;     // 'nomodifiable'
@@ -241,8 +241,8 @@ void terminal_open(Terminal **termpp, buf_T *buf, TerminalOptions opts)
   buf->b_p_scbk =          // 'scrollback' (initialize local from global)
                   (p_scbk < 0) ? 10000 : MAX(1, p_scbk);
   buf->b_p_tw = 0;         // 'textwidth'
-  set_option_value("wrap", BOOLEAN_OPTVAL(false), OPT_LOCAL);
-  set_option_value("list", BOOLEAN_OPTVAL(false), OPT_LOCAL);
+  set_option_value(kOptWrap, BOOLEAN_OPTVAL(false), OPT_LOCAL);
+  set_option_value(kOptList, BOOLEAN_OPTVAL(false), OPT_LOCAL);
   if (buf->b_ffname != NULL) {
     buf_set_term_title(buf, buf->b_ffname, strlen(buf->b_ffname));
   }