docs: Add READMEs for fish, vim, and xmodmap

Since I'd like other people to try my dotfiles, I will be writing
READMEs for each package directory, which should hopefully cover
anything a user needs to do in order to use the package.

fish/README.md

@@ -0,0 +1,19 @@
+# fish - the friendly interactive shell
+
+I use fish as my default shell of choice, and write scripts in `sh`.
+
+## Dependencies
+
+- `fish` - The friendly interactive shell
+- `exa` - Drop-in replacement for `ls` and `tree`
+- Any other features that you want to use (git abbreviations, etc.)
+
+## Installation
+
+```sh
+make package=fish
+```
+
+## Usage
+
+The dotfiles are automatically applied when you start fish.

vim/README.md

@@ -0,0 +1,31 @@
+# Vim
+
+I use neovim as my main text editor, and vim elsewhere.
+
+## Dependencies
+
+- `vim` - If you're reading this, you probably already know what vim is
+- `neovim` - An improved version of vim (cursor modes, sane defaults, etc.)
+- `wal` - Changing color schemes support
+- `fzf` - Fuzzy search support
+- `ripgrep` - Jump between lines in files
+- `git` - Git diff support
+- Any other features you want to use (e.g. TeX support with `texlive`)
+
+## Installation
+
+```sh
+make package=vim
+```
+
+## Usage
+
+I use [vim-plug][vim-plug] as my plugin manager of choice. Install it, then run:
+
+```
+vim +PlugInstall +qall
+```
+
+Now you can use my vim config with all the plugins installed!
+
+[vim-plug]: https://github.com/junegunn/vim-plug

xmodmap/README.md

@@ -0,0 +1,30 @@
+# xmodmap
+
+I use xmodmap with xcape to make Caps Lock function as Escape when pressed and Ctrl when held down.
+
+## Dependencies
+
+- `xorg-xmodmap` - Used to make caps lock work as ctrl
+- `xcape` - Used to make caps lock work as escape
+
+## Installation
+
+```sh
+make package=xmodmap
+```
+
+## Usage
+
+Start `xmodmap` in one of your init scripts, like so:
+
+```sh
+# Make caps lock work as ctrl
+xmodmap ~/.xmodmap
+```
+
+To make caps lock work as Escape, start xcape as well:
+
+```sh
+# Make caps lock (left ctrl) work as escape
+xcape -e 'Control_L=Escape'
+```