Update templates_doc.go

[geeknik]

Typo fix

[forgedhallpass]

The SYNTAX-REFERENCE.md is auto-generated, so there is no point making changes there, because it will be overwritten either way.

[geeknik]

The SYNTAX-REFERENCE.md is auto-generated, so there is no point making changes there, because it will be overwritten either way.

Thanks, I realized that after I made the commit. (;