replace remaining occurrences of `Spring Tools 4` with `Spring Tools`

[martinlippert]

Following the final rename from Spring Tools 4 to just Spring Tools, we should replace the remaining occurrences of the Spring Tools 4 name with Spring Tools

[anbusampath]

Will Eclipse based distribution continue to use "Spring Tool Suite 4" name?

[martinlippert]

Will Eclipse based distribution continue to use "Spring Tool Suite 4" name?

No. We will slowly move towards "Spring Tool Suite" (without the "4"), then move forward to just use "Spring Tools" in the longer run.