vim-patch:8.2.4925: trailing backslash may cause reading past end of line (#18493)

Problem:    Trailing backslash may cause reading past end of line.
Solution:   Check for NUL after backslash.
53a70289c2

N/A patches for version.c:

vim-patch:8.2.4926: #ifdef for crypt feature around too many lines

Problem:    #ifdef for crypt feature around too many lines.
Solution:   Move code outside of #ifdef. (closes vim/vim#10388)
51f0bc31d3

src/nvim/search.c

@@ -3969,6 +3969,9 @@ static int find_next_quote(char_u *line, int col, int quotechar, char_u *escape)
       return -1;
     } else if (escape != NULL && vim_strchr(escape, c)) {
       col++;
+      if (line[col] == NUL) {
+        return -1;
+      }
     } else if (c == quotechar) {
       break;
     }