Update docs links and add build/ to .gitignore

Author: ernestognw

.gitignore

@@ -37,6 +37,7 @@ npm-debug.log
 
 # docs artifacts
 docs/modules/api
+build/
 
 # only used to package @openzeppelin/contracts
 contracts/build/

docs/templates/contract.hbs

@@ -4,11 +4,11 @@
 
 [.contract]
 [[{{anchor}}]]
-=== `++{{name}}++` link:https://github.com/OpenZeppelin/openzeppelin-contracts/blob/v{{oz-version}}/{{__item_context.file.absolutePath}}[{github-icon},role=heading-link]
+=== `++{{name}}++` link:https://github.com/OpenZeppelin/openzeppelin-community-contracts/blob/master/{{__item_context.file.absolutePath}}[{github-icon},role=heading-link]
 
 [.hljs-theme-light.nopadding]
 ```solidity
-import "@openzeppelin/{{__item_context.file.absolutePath}}";
+import "@openzeppelin/community-{{__item_context.file.absolutePath}}";
 ```
 
 {{{natspec.dev}}}