docs: add development_guidelines.md

This file focuses on the requirements and steps needed to make an
acceptable PR.

.github/pull_request_template.md

@@ -12,8 +12,8 @@ Steps for reviewers to follow to test the change.
 
 ### Code Style and Documentation
 - [ ] The change is not [insubstantial](https://github.com/lightningnetwork/lnd/blob/master/docs/code_contribution_guidelines.md#substantial-contributions-only). Typo fixes are not accepted to fight bot spam.
-- [ ] The change obeys the [Code Documentation and Commenting](https://github.com/lightningnetwork/lnd/blob/master/docs/code_contribution_guidelines.md#code-documentation-and-commenting) guidelines, and lines wrap at 80.
-- [ ] Commits follow the [Ideal Git Commit Structure](https://github.com/lightningnetwork/lnd/blob/master/docs/code_contribution_guidelines.md#ideal-git-commit-structure).
+- [ ] The change obeys the [Code Documentation and Commenting](https://github.com/lightningnetwork/lnd/blob/master/docs/development_guidelines.md#code-documentation-and-commenting) guidelines, and lines wrap at 80.
+- [ ] Commits follow the [Ideal Git Commit Structure](https://github.com/lightningnetwork/lnd/blob/master/docs/development_guidelines.md#ideal-git-commit-structure).
 - [ ] Any new logging statements use an appropriate subsystem and logging level.
 - [ ] Any new lncli commands have appropriate tags in the comments for the rpc in the proto file.
 - [ ] [There is a change description in the release notes](https://github.com/lightningnetwork/lnd/tree/master/docs/release-notes), or `[skip ci]` in the commit message for small changes.