The `swift-mode` REPL bindings have been updated to use a different
naming convention (e.g. a prefix of `swift-mode:` in the CL style).
Typing `, s s` would trigger this error:
```
command-execute: Wrong type argument: commandp, swift-mode-run-repl
```
This change fixes up the command names so that they are usable again
from the leader key.
By convention, code markup (`~`) is reserved for keybindings in Org-based
documentation in Spacemacs. Verbatim markup (`=`) is reserved for code and
other code-like things. So change several readmes to reflect this convention.
Use verbatim markup for things like (non-exhaustive list):
- Emacs Lisp functions, modes, buffers, etc.
- Environment variables
- Directory paths
- Code in general
