bug: improves SEO score

[Meng-Heng]

1. Title tag is missing

• https://help.keyman.com/developer/engine/web/current-version/guide/examples/__full-manual-control
• https://help.keyman.com/developer/engine/web/current-version/guide/examples/__control-by-control
• https://help.keyman.com/developer/engine/web/current-version/guide/examples/__auto-control
• https://help.keyman.com/developer/engine/web/current-version/guide/examples/__manual-control
• https://help.keyman.com/developer/engine/web/18.0/guide/examples/__control-by-control.html
• https://help.keyman.com/developer/engine/web/18.0/guide/examples/__manual-control.html
• https://help.keyman.com/developer/engine/web/18.0/guide/examples/__auto-control.html
• https://help.keyman.com/developer/engine/web/18.0/guide/examples/__full-manual-control.html

2. Broken or invalid HTML

• https://help.keyman.com/developer/6.0/reference/_struct_silkey
• https://help.keyman.com/developer/12.0/guides/develop/imx/guide_imx_web
• https://help.keyman.com/developer/9.0/guides/develop/imx/guide_imx_web
• https://help.keyman.com/developer/13.0/guides/develop/imx/guide_imx_web
• https://help.keyman.com/developer/10.0/guides/develop/imx/guide_imx_web
• https://help.keyman.com/developer/11.0/guides/develop/imx/guide_imx_web

3. HTML is missing or empty

• https://help.keyman.com/products/windows/8.0/docs/context_tutorial

[darcywong00]

The web/18.0 and web/current-version links will be in the main repo

https://github.com/keymanapp/keyman/tree/master/web/docs/engine/guide/examples