patch 8.2.3914: various spelling mistakes in comments

Problem:    Various spelling mistakes in comments.
Solution:   Fix the mistakes. (Dominique Pellé, closes #9416)
diff --git a/src/scriptfile.c b/src/scriptfile.c
index 129d4d6..9c8f1ef 100644
--- a/src/scriptfile.c
+++ b/src/scriptfile.c
@@ -1307,7 +1307,7 @@
 
     current_sctx.sc_lnum = 0;
 
-    // Check if this script was sourced before to finds its SID.
+    // Check if this script was sourced before to find its SID.
     // Always use a new sequence number.
     current_sctx.sc_seq = ++last_current_SID_seq;
     if (sid > 0)