v1.5.6

Changelog

02b902d Add GitHub Release badge
2566544 Add doctor version check
d17f54f Add doctor version check (#318)
e3b79bb Add fish completion support
a4aaed0 Add fish completion support (#320)
e40b797 Add fish to completion command description
f01f715 Add golangci-lint configuration
e34b215 Add install-tools target
f2cf3b8 Disable warning about computed URL
fa33f40 Don't use a singleton NullMutator instance
e2edc9e Don't use references to range-scoped variables
1abbee1 Explain how to customise the merge tool
e7576f4 Improve documentation
ae968e3 Make script state bucket a parameter, not a global
23c0169 Mark snap releases as stable
36bbdcd Mark snap releases as stable (#317)
fd8a72e Remove Go Report Card badge
802b3b1 Remove pre-release-checks target
f4c9963 Resolve all lint problems and enable more linters (#310)
f7ca727 Update badges (#311)
a324c18 Update contribution docs
de73d1b Update contribution docs (#309)
dac85d2 Update go.mod
3073691 Update snap install instructions with beta channel
b006026 Update snap install instructions with beta channel (#307)
1b047e6 Use latest go-difflib with improved colors
377bed9 Use latest go-difflib with improved colors (#328)
24cb155 Use latest go-vfs with Windows support
6963cb9 Use latest go-vfs with Windows support (#319)
b0182fe Use relative package paths in documentation
07244d3 Use simpler interfaces where possible
dadd7fa go mod tidy to make CI happy