Add Coercing Casing With vim-abolish as a vim til.

vim/coercing-casing-with-vim-abolish.md

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+# Coercing Casing With vim-abolish
+
+The [`vim-abolish`](https://github.com/tpope/vim-abolish) plugin provides a
+couple handy shortcuts for quickly coercing the casing of a variable.
+
+For instance, if you have a variable in camel case and you want to change it
+snake case, you can navigate over the variable and hit `crs` (e.g.
+`myFavoriteVariable` -> `my_favorite_variable`).
+
+Similarly, you can hit `crc` to change a variable to camel case.
+
+It even has support for mixed case (`crm`) and uppercase (`cru`).