[1.7.x] Fixed typo in docs/ref/templates/builtins.txt
[1.7.x] Fixed typo in docs/ref/templates/builtins.txt

Backport of 48ddc66219deaac2aa5fa3d2cb0f420404d6b8ec from master

jyotsna1820/django,jyotsna1820/django,jyotsna1820/django,oscaro/django,oscaro/django,oscaro/django,oscaro/django,jyotsna1820/django