docs: update .vuepress/config.js (#5043)

## Description

![image](https://user-images.githubusercontent.com/1021101/86193320-7aa13200-bb00-11ea-95ac-aa6468ab7f46.png)


### Next steps:
- [x] bump vuepress-theme-cosmos version
- [x] tweak config.js
- [x] update color variables
- [x] sh, shell → bash for syntax highlighting

docs/tools/debugging.md

@@ -9,7 +9,7 @@ state, the node' status, the WAL, and even the stack trace of the process
 before exit. These files can be useful to examine when debugging a faulty
 Tendermint process.
 
-```sh
+```bash
 tendermint debug kill <pid> </path/to/out.zip> --home=</path/to/app.d>
 ```
 
@@ -36,7 +36,7 @@ compressed archives at a regular interval. These archives contain the goroutine
 and heap profiles in addition to the consensus state, network info, node
 status, and even the WAL.
 
-```sh
+```bash
 tendermint debug dump </path/to/out> --home=</path/to/app.d>
 ```