Ignore mutations inside string literals

[dirtcrusher]

I removed the generation of patches inside string literals.

For projects containing debug/logging statements using = or / in them, this created a lot of patches. For example, the following line would generate 51 patches:

printf("roll = %.2f / pitch = %.2f / yaw = %.2f", roll, pitch, yaw);

Since it is a simple debug logging statement (and therefore not really useful to be tested), none of these patches were actually useful.

[nlohmann]

Thanks a lot!