fix(upstream): language servers shouldn't be launched through package managers or interpreters

[WieeRd]

As mentioned in #2, some servers in lspconfig are launched through package manager / language interpreter executables and not their own executables. They are blacklisted as false positives of executable availability check.

dotnet
java
nc
node
npx
perl
python
python3

I think these are against the principle of making the least assumptions about the user's system, and should be fixed in the upstream. For example, pyright can also be installed using npm / npx yet its cmd is registered as pyright. Inconsistency with rest of the node based language servers. Servers launched through python -m <server> can be installed using pipx and they will be made available to ~/.local/bin. I will work on PRs to fix server configurations like this.