GitHub uses https://github.com/github/linguist to do language stats.
linguist however mis-detects a bunch of things in this repo. It also
needs to be told about the "vendored" files in the repo.
This can be fixed by setting values via `.gitattributes` file which is
done here.
Before
```
74.90% Coq
13.42% Python
3.71% C++
3.62% Tcl
1.42% Makefile
1.26% Verilog
0.73% JavaScript
0.62% Shell
0.10% HTML
0.08% XSLT
0.07% CMake
0.03% Assembly
0.02% Ruby
0.01% Dockerfile
```
After
```
42.45% Python
25.18% Verilog
12.00% C++
10.96% Tcl
4.07% Makefile
2.34% JavaScript
1.99% Shell
0.34% HTML
0.26% XSLT
0.22% CMake
0.09% Assembly
0.08% Ruby
0.03% Dockerfile
```
Signed-off-by: Tim 'mithro' Ansell <me@mith.ro>