* [Website] Add titles and labels to iframes and images on Community pages
**what is the change?:**
- add titles to all iframes
- add alt tags to images
- add `aria-label` to some links which only have images as contents.
**why make this change?:**
Based on warnings thrown by aXe a11y audit of those pages
**test plan:**
Manual testing
**issue:**
None
* remove redundant alt tags
This documentation change clarifies how the method `tick()` relates to the example given in the State and Lifecycle documentation. Why this change is necessary is because it may be confusing for beginners who may mistake `tick()` to be a lifecycle API hook. To clarify, the verbiage is changed so that it becomes more clear that the method is specific to the component and not the API.
* Use ES6 module instead of commonJS
As far as I know, we're using ES6 modules throughout the docs. For the sake of consistency :)
* Convert all CommonJS requires to ES6 module
* [Gatsby docs a11y] Add `aria-label` to search input
**what is the change?:**
See title.
**why make this change?:**
There was no label on this input, and screen readers might not have been
able to identify it's purpose.
[The `placeholder` doesn't count as a label.](http://a11yproject.com/posts/placeholder-input-elements/)
**test plan:**
Manually inspected the HTML in the devtools, and ran the aXe a11y audit
tool, and the warning generated by aXe was gone.
**issue:**
Checklist item on list of docs a11y issues -
https://github.com/bvaughn/react/wiki/Gatsby-A11y-Fixes
* [Gatsby Docs a11y] Increase contrast of 'installation' page tabs
**what is the change?:**
Change the dark blue used for the text/background of the tabs on the
'installation' page to a slightly darker blue, which we were already
using for the 'focus' style of the tabs. It looked a bit weird before,
imo, when the 'focus' was darker.
Now the 'focus' style just lightens the border to the new signature
blue.
**why make this change?:**
To add enough contrast that folks who see colors differently can still
decipher the writing on the tabs on this page.
We plan to refactor this page and remove the tabs soon, so not too
worried about making this fix perfect.
**test plan:**
Manual testing - loaded the page and it looks ok, and ran aXe a11y
audit, no more warnings about contrast. :)
(Flarnie will insert a screenshot)
**issue:**
checklist item on https://github.com/bvaughn/react/wiki/Gatsby-A11y-Fixes
