doc: fix broken links

Links in documentation shouldn't point to dead ends.

doc/languages-frameworks/gnome.section.md

@@ -92,7 +92,7 @@ For convenience, it also adds `dconf.lib` for a GIO module implementing a GSetti
 
 - []{#ssec-gnome-hooks-glib} `glib` setup hook will populate `GSETTINGS_SCHEMAS_PATH` and then `wrapGAppsHook` will prepend it to `XDG_DATA_DIRS`.
 
-- []{#ssec-gnome-hooks-gdk-pixbuf} `gdk-pixbuf` setup hook will populate `GDK_PIXBUF_MODULE_FILE` with the path to biggest `loaders.cache` file from the dependencies containing [GdkPixbuf loaders](ssec-gnome-gdk-pixbuf-loaders). This works fine when there are only two packages containing loaders (`gdk-pixbuf` and e.g. `librsvg`) – it will choose the second one, reasonably expecting that it will be bigger since it describes extra loader in addition to the default ones. But when there are more than two loader packages, this logic will break. One possible solution would be constructing a custom cache file for each package containing a program like `services/x11/gdk-pixbuf.nix` NixOS module does. `wrapGAppsHook` copies the `GDK_PIXBUF_MODULE_FILE` environment variable into the produced wrapper.
+- []{#ssec-gnome-hooks-gdk-pixbuf} `gdk-pixbuf` setup hook will populate `GDK_PIXBUF_MODULE_FILE` with the path to biggest `loaders.cache` file from the dependencies containing [GdkPixbuf loaders](#ssec-gnome-gdk-pixbuf-loaders). This works fine when there are only two packages containing loaders (`gdk-pixbuf` and e.g. `librsvg`) – it will choose the second one, reasonably expecting that it will be bigger since it describes extra loader in addition to the default ones. But when there are more than two loader packages, this logic will break. One possible solution would be constructing a custom cache file for each package containing a program like `services/x11/gdk-pixbuf.nix` NixOS module does. `wrapGAppsHook` copies the `GDK_PIXBUF_MODULE_FILE` environment variable into the produced wrapper.
 
 - []{#ssec-gnome-hooks-gtk-drop-icon-theme-cache} One of `gtk3`’s setup hooks will remove `icon-theme.cache` files from package’s icon theme directories to avoid conflicts. Icon theme packages should prevent this with `dontDropIconThemeCache = true;`.
 

doc/languages-frameworks/lua.section.md

@@ -128,7 +128,7 @@ Let's present the luarocks way first and the manual one in a second time.
 
 ### Packaging a library on luarocks {#packaging-a-library-on-luarocks}
 
-[Luarocks.org](www.luarocks.org) is the main repository of lua packages.
+[Luarocks.org](https://luarocks.org/) is the main repository of lua packages.
 The site proposes two types of packages, the rockspec and the src.rock
 (equivalent of a [rockspec](https://github.com/luarocks/luarocks/wiki/Rockspec-format) but with the source).
 These packages can have different build types such as `cmake`, `builtin` etc .

doc/languages-frameworks/vim.section.md

@@ -309,9 +309,9 @@ Sample output2:
 
 ## Adding new plugins to nixpkgs {#adding-new-plugins-to-nixpkgs}
 
-Nix expressions for Vim plugins are stored in [pkgs/misc/vim-plugins](/pkgs/misc/vim-plugins). For the vast majority of plugins, Nix expressions are automatically generated by running [`./update.py`](/pkgs/misc/vim-plugins/update.py). This creates a [generated.nix](/pkgs/misc/vim-plugins/generated.nix) file based on the plugins listed in [vim-plugin-names](/pkgs/misc/vim-plugins/vim-plugin-names). Plugins are listed in alphabetical order in `vim-plugin-names` using the format `[github username]/[repository]@[gitref]`. For example https://github.com/scrooloose/nerdtree becomes `scrooloose/nerdtree`.
+Nix expressions for Vim plugins are stored in [pkgs/misc/vim-plugins](https://github.com/NixOS/nixpkgs/tree/master/pkgs/misc/vim-plugins). For the vast majority of plugins, Nix expressions are automatically generated by running [`./update.py`](https://github.com/NixOS/nixpkgs/blob/master/pkgs/misc/vim-plugins/update.py). This creates a [generated.nix](https://github.com/NixOS/nixpkgs/blob/master/pkgs/misc/vim-plugins/generated.nix) file based on the plugins listed in [vim-plugin-names](https://github.com/NixOS/nixpkgs/blob/master/pkgs/misc/vim-plugins/vim-plugin-names). Plugins are listed in alphabetical order in `vim-plugin-names` using the format `[github username]/[repository]@[gitref]`. For example https://github.com/scrooloose/nerdtree becomes `scrooloose/nerdtree`.
 
-Some plugins require overrides in order to function properly. Overrides are placed in [overrides.nix](/pkgs/misc/vim-plugins/overrides.nix). Overrides are most often required when a plugin requires some dependencies, or extra steps are required during the build process. For example `deoplete-fish` requires both `deoplete-nvim` and `vim-fish`, and so the following override was added:
+Some plugins require overrides in order to function properly. Overrides are placed in [overrides.nix](https://github.com/NixOS/nixpkgs/blob/master/pkgs/misc/vim-plugins/overrides.nix). Overrides are most often required when a plugin requires some dependencies, or extra steps are required during the build process. For example `deoplete-fish` requires both `deoplete-nvim` and `vim-fish`, and so the following override was added:
 
 ```nix
 deoplete-fish = super.deoplete-fish.overrideAttrs(old: {