Use const/let in sample code

[chasenlehara]

It’d be nice for all of the code in our guides and core APIs to show const/let; extra points for having all of our example code show const/let instead of var.

Note that this is not talking about the source code, where we intend to continue using what’s supported by the browsers we support.

[christopherjbaker]

The following PRs have been opened:

• Cleanup markdown sample code can-define-list#2
• Cleanup markdown sample code can-connect#408
• Cleanup markdown sample code can-set#85
• Cleanup markdown sample code can-vdom#44
• Cleanup markdown sample code can-validate#71
• Cleanup markdown sample code can-observe#46
• Cleanup markdown sample code can-fixture#146
• Cleanup markdown sample code can-zone#163
• Cleanup markdown sample code can-define#317
• Cleanup markdown sample code can-view-href#47
• Cleanup markdown sample code can-util#415
• Cleanup markdown sample code can-compute#128
• Cleanup markdown sample code can-component#222
• Cleanup markdown sample code can-construct#54
• Cleanup markdown sample code can-route#155
• Cleanup markdown sample code can-event#76
• Cleanup markdown sample code can-stache-bindings#430
• Cleanup markdown sample code can-view-callbacks#82
• Cleanup markdown sample code can-view-import#100
• Cleanup markdown sample code can-view-nodelist#44
• Cleanup markdown sample code can-view-parser#89
• Cleanup markdown sample code can-view-scope#150
• Cleanup markdown sample code can-view-target#61
• Cleanup markdown sample code can-observation#126
• Cleanup markdown sample code can-stache#465
• Cleanup markdown sample code can-view-model#63
• Cleanup markdown sample code can-route-pushstate#87
• Cleanup markdown sample code can-connect-feathers#105
• Cleanup markdown sample code can-simple-map#60
• Cleanup markdown sample code can-stream-kefir#64
• Cleanup markdown sample code can-stache-converters#80
• Cleanup markdown sample code can-define-stream#60
• Cleanup markdown sample code can-fixture-socket#61
• Cleanup markdown sample code can-define-backup#7
• Cleanup markdown sample code can-validate-validatejs#21
• Cleanup markdown sample code can-connect-signalr#37
• Cleanup markdown sample code can-zone-storage#14
• Cleanup markdown sample code can-define-stream-kefir#28
• Cleanup markdown sample code can-define-validate-validatejs#48
• Cleanup markdown sample code can-parse#7
• Cleanup markdown sample code can-element#49
• Cleanup markdown sample code can-connect-cloneable#19
• Cleanup markdown sample code can-ndjson-stream#30
• Cleanup markdown sample code can-connect-ndjson#14
• Cleanup markdown sample code can-symbol#25
• Cleanup markdown sample code can-reflect#101
• Cleanup markdown sample code can-migrate#69
• Cleanup markdown sample code can-param#9
• Cleanup markdown sample code can-stream#13
• Cleanup markdown sample code can-global#2
• Cleanup markdown sample code can-is-browser-window#1
• Cleanup markdown sample code can-globals#40
• Cleanup markdown sample code can-stache-animate#47
• Cleanup markdown sample code can-validate-interface#12
• Cleanup markdown sample code can-make-rest#17
• Cleanup markdown sample code can-dom-mutate#29
• Cleanup markdown sample code can-stache-key#27
• Cleanup markdown sample code can-debug#39
• Cleanup markdown sample code can-attribute-encoder#16
• Cleanup markdown sample code can-kefir#15
• Cleanup markdown sample code can-test-helpers#11
• Cleanup markdown sample code can-queues#14
• Cleanup markdown sample code can-jsx#7
• Cleanup markdown sample code can-compute-memoize#10
• Cleanup markdown sample code can-key-tree#10
• Cleanup markdown sample code can-simple-observable#19
• Cleanup markdown sample code can-define-lazy-value#4
• Cleanup markdown sample code can-event-queue#16
• Cleanup markdown sample code can-observation-recorder#6
• Cleanup markdown sample code can-stache-route-helpers#4
• Cleanup markdown sample code can-reflect-dependencies#14
• Cleanup markdown sample code can-reflect-tests#7
• Cleanup markdown sample code can-stache-helpers#3
• Cleanup markdown sample code can-define-map#1

[chasenlehara]

This has not been finished.