fix(api): clamp range lines in `nvim__redraw()` (#31710)

Problem:
`nvim__redraw()` doesn't clamp the lines in the `range` parameter before truncating to int. The resulting range may be empty when the original range contained buffer lines and vice versa.

E.g. for a buffer with 4 lines, these are the redrawn lines:

```lua
{ 2, 2 ^ 31 } -> none (should be { 2, 3 })
{ 2, 2 ^ 32 } -> none (should be { 2, 3 })
{ 2 ^ 32 - 1, 2 } -> { 0, 1 } (should be none)
```

Solution:
Clamp `range` values before truncating to int.

1 files changed, 15 insertions, 5 deletions

diff --git a/src/nvim/api/vim.c b/src/nvim/api/vim.c
index 332c5bc15c..25f44bb4eb 100644
--- a/src/nvim/api/vim.c
+++ b/src/nvim/api/vim.c
@@ -2374,13 +2374,23 @@ void nvim__redraw(Dict(redraw) *opts, Error *err)
              "%s", "Invalid 'range': Expected 2-tuple of Integers", {
       return;
     });
-    linenr_T first = (linenr_T)kv_A(opts->range, 0).data.integer + 1;
-    linenr_T last = (linenr_T)kv_A(opts->range, 1).data.integer;
+    int64_t begin_raw = kv_A(opts->range, 0).data.integer;
+    int64_t end_raw = kv_A(opts->range, 1).data.integer;
+
     buf_T *rbuf = win ? win->w_buffer : (buf ? buf : curbuf);
-    if (last == -1) {
-      last = rbuf->b_ml.ml_line_count;
+    linenr_T line_count = rbuf->b_ml.ml_line_count;
+
+    int begin = (int)MIN(begin_raw, line_count);
+    int end;
+    if (end_raw == -1) {
+      end = line_count;
+    } else {
+      end = (int)MIN(MAX(begin, end_raw), line_count);
+    }
+
+    if (begin < end) {
+      redraw_buf_range_later(rbuf, 1 + begin, end);
     }
-    redraw_buf_range_later(rbuf, first, last);
   }
 
   // Redraw later types require update_screen() so call implicitly unless set to false.