feat: improve 'no go files to analyze' message

[ldez]

90% of the contexts that lead to no go files to analyze error are related to missing go mod tidy.

A sample of issues on the topic:

• ERRO Running error: context loading failed: no go files to analyze #4168
• no go files to analyze #3371
• no go files to analyze  #3335
• ERRO Running error: context loading failed: no go files to analyze #1855
• golangci-lint run cannot find golang files in the current directory #1833
• Docker version golangci/golangci-lint:v1.37.1 raise "no go files to analyze" #1784
• level=error msg="Running error: context loading failed: package github.com/sirupsen/logrus: no go files to analyze" #870
• context loading failed: no go files to analyze #825

Before:

$ golangci-lint run ./...                           
ERRO Running error: context loading failed: no go files to analyze 

After:

$ ./golangci-lint run ./...                                                     
ERRO Running error: context loading failed: no go files to analyze: running `go mod tidy` may solve the problem 

Fixes #3335
Fixes #825

[nyetwurk]

This isn't terribly useful, it would be good to have more information about what is going on in that dedupilication step.

See #825 (comment)

[ldez]

As I said in the description: it's useful in 90% of the cases, then it's not perfect.

If you want more information about the deduplication step, you just have to run the following command:

GL_DEBUG=loader golangci-lint run