Restore public modifiers with javadoc

[timtebeek]

What's changed?

• Resttore public modifiers for template classes, as needed on Java 11+
• Add JavaDoc on template classes, to reduce warnings on error-prone- support
• Always print clickable link with notes

Before

[INFO] /error-prone-support/error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/ImmutableSortedMapRules.java:[24,16] Generics are currently not supported
[INFO] com.google.errorprone.refaster.Refaster is not supported
[INFO] The @UseImportPolicy is currently not supported
[INFO] /error-prone-support/error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/LongStreamRules.java:[66,25] The @Placeholder is currently not supported
[INFO] The @AlsoNegation is currently not supported
[INFO] The @DoNotCall is currently not supported
[INFO] The @Repeated annotation is currently not supported
[INFO] The @Matches annotation is currently not supported

After

[INFO] /error-prone-support/error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/ImmutableSortedMapRules.java:[24,16] Generics are currently not supported
[INFO] /error-prone-support/error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/EqualityRules.java:[85,16] com.google.errorprone.refaster.Refaster is currently not supported
[INFO] /error-prone-support/error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/MockitoRules.java:[26,16] @UseImportPolicy is currently not supported
[INFO] /error-prone-support/error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/LongStreamRules.java:[64,19] @Placeholder is currently not supported
[INFO] /error-prone-support/error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/BigDecimalRules.java:[72,16] @AlsoNegation is currently not supported
[INFO] /error-prone-support/error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/TestNGToAssertJRules.java:[80,16] @DoNotCall is currently not supported
[INFO] /error-prone-support/error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/WebClientRules.java:[179,16] @Repeated is currently not supported
[INFO] /error-prone-support/error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/ReactorRules.java:[1585,16] @Matches is currently not supported

What's your motivation?

Makes things work on Java 11 and in error-prone-support