chore: generate stable wiki file directly

Author: saecki

Makefile

@@ -15,4 +15,3 @@ release:
 	@test $${RELEASE_VERSION?Please set environment variable RELEASE_VERSION}
 	echo "${RELEASE_VERSION}" > docgen/shared/stable.txt
 	nvim -l docgen/gen_doc.lua
-	mv docgen/wiki/Documentation-unstable.md "docgen/wiki/Documentation-${RELEASE_VERSION}.md"

docgen/gen_doc.lua

@@ -457,7 +457,7 @@ end
 local function gen_docs()
     gen_vim_doc()
     gen_markdown("docgen/templates/README.md.in", "README.md")
-    gen_markdown("docgen/templates/documentation.md.in", "docgen/wiki/Documentation-unstable.md")
+    gen_markdown("docgen/templates/documentation.md.in", string.format("docgen/wiki/Documentation-%s.md", version))
 end
 
 gen_docs()