docs: do not name a C function parameter sql

55d43d2 rejects `sql` as a parameter name, so the "Calling C from
V" SQLite example no longer compiled:

    error: unexpected keyword `sql`, expecting name

That is one of the two examples that make `check-markdown` fail on
master. Rename the parameter of `C.sqlite3_exec` to `query`.

Co-Authored-By: WOZCODE <contact@withwoz.com>

Author: PythonWillRule

doc/docs.md

@@ -8857,7 +8857,7 @@ fn C.sqlite3_step(&C.sqlite3_stmt)
 
 fn C.sqlite3_finalize(&C.sqlite3_stmt)
 
-fn C.sqlite3_exec(db &C.sqlite3, sql &char, cb FnSqlite3Callback, cb_arg voidptr, emsg &&char) int
+fn C.sqlite3_exec(db &C.sqlite3, query &char, cb FnSqlite3Callback, cb_arg voidptr, emsg &&char) int
 
 fn C.sqlite3_free(voidptr)