set devbranch for docs to main (#486)

* set devbranch for docs to main

* fix references to master in docs

* formatting

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

Author: oxinabox

README.md

@@ -3,13 +3,13 @@
 # ChainRulesCore
 
 [![Build Status](https://github.com/JuliaDiff/ChainRulesCore.jl/workflows/CI/badge.svg)](https://github.com/JuliaDiff/ChainRulesCore.jl/actions?query=workflow:CI)
-[![Coverage](https://codecov.io/gh/JuliaDiff/ChainRulesCore.jl/branch/master/graph/badge.svg)](https://codecov.io/gh/JuliaDiff/ChainRulesCore.jl)
+[![Coverage](https://codecov.io/gh/JuliaDiff/ChainRulesCore.jl/branch/main/graph/badge.svg)](https://codecov.io/gh/JuliaDiff/ChainRulesCore.jl)
 [![Code Style: Blue](https://img.shields.io/badge/code%20style-blue-4495d1.svg)](https://github.com/invenia/BlueStyle)
 [![ColPrac: Contributor's Guide on Collaborative Practices for Community Packages](https://img.shields.io/badge/ColPrac-Contributor's%20Guide-blueviolet)](https://github.com/SciML/ColPrac)
 [![DOI](https://zenodo.org/badge/199721843.svg)](https://zenodo.org/badge/latestdoi/199721843)
 
 **Docs:**
-[![](https://img.shields.io/badge/docs-master-blue.svg)](https://juliadiff.org/ChainRulesCore.jl/dev)
+[![](https://img.shields.io/badge/docs-main-blue.svg)](https://juliadiff.org/ChainRulesCore.jl/dev)
 [![](https://img.shields.io/badge/docs-stable-blue.svg)](https://juliadiff.org/ChainRulesCore.jl/stable)
 
 The ChainRulesCore package provides a light-weight dependency for defining sensitivities for functions in your packages, without you needing to depend on ChainRules itself.

docs/make.jl

@@ -67,4 +67,6 @@ makedocs(;
     checkdocs=:exports,
 )
 
-deploydocs(; repo="github.com/JuliaDiff/ChainRulesCore.jl.git", push_preview=true)
+deploydocs(;
+    repo="github.com/JuliaDiff/ChainRulesCore.jl.git", devbranch="main", push_preview=true
+)

docs/src/arrays.md

@@ -814,7 +814,7 @@ See the [implementation in ChainRules](https://github.com/JuliaDiff/ChainRules.j
 
 ## More examples
 
-For more instructive examples of array rules, see [^Giles2008ext] (real vector and matrix rules) and the [LinearAlgebra rules in ChainRules](https://github.com/JuliaDiff/ChainRules.jl/tree/master/src/rulesets/LinearAlgebra).
+For more instructive examples of array rules, see [^Giles2008ext] (real vector and matrix rules) and the [LinearAlgebra rules in ChainRules](https://github.com/JuliaDiff/ChainRules.jl/tree/main/src/rulesets/LinearAlgebra).
 For differentiating the LU decomposition, see [this blog post by Seth Axen](https://sethaxen.com/blog/2021/02/differentiating-the-lu-decomposition/).
 
 ## References

docs/src/opting_out_of_rules.md

@@ -8,7 +8,7 @@ If this is generally the case, then we should not have the rule defined at all.
 But if it is only the case for a particular set of types, then we want to opt-out just that one.
 This is done with the [`@opt_out`](@ref) macro.
 
-Consider one a `rrule` for `sum` (the following simplified from the one in [ChainRules.jl](https://github.com/JuliaDiff/ChainRules.jl/blob/master/src/rulesets/Base/mapreduce.jl) itself)
+Consider one a `rrule` for `sum` (the following simplified from the one in [ChainRules.jl](https://github.com/JuliaDiff/ChainRules.jl/blob/main/src/rulesets/Base/mapreduce.jl) itself)
 ```julia
 function rrule(::typeof(sum), x::AbstractArray{<:Number})
     y = sum(x; dims=dims)