package com.jokerzoid.intellij.plugin.stylelint;

import com.intellij.lang.annotation.AnnotationHolder;
import com.intellij.lang.annotation.ExternalAnnotator;
import com.intellij.openapi.diagnostic.Logger;
import com.intellij.openapi.editor.Editor;
import com.intellij.psi.PsiElement;
import com.intellij.psi.PsiFile;
import com.intellij.psi.util.PsiUtil;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;

import java.util.List;

/**
 * @author Raul
 */
public class StylelintAnnotator extends ExternalAnnotator<PsiFile, List<StylelintWarning>> {
    private static final Logger LOGGER = Logger.getInstance(StylelintAnnotator.class);

    public StylelintAnnotator() {
        LOGGER.info("StylelintAnnotator");
    }

    @Nullable
    @Override
    public PsiFile collectInformation(@NotNull PsiFile file) {
        return file;
    }

    @Nullable
    @Override
    public PsiFile collectInformation(@NotNull PsiFile file, @NotNull Editor editor, boolean hasErrors) {
        return super.collectInformation(file, editor, hasErrors);
    }

    @Nullable
    @Override
    public List<StylelintWarning> doAnnotate(PsiFile file) {
        final StylelintOutput output = ProcessManager.runStylelint(file);

        return output.getWarnings();
    }

    @Override
    public void apply(@NotNull PsiFile file, List<StylelintWarning> warnings, @NotNull AnnotationHolder holder) {
        warnings.forEach(warning -> {
            final PsiElement element = PsiUtil.getElementAtOffset(file, warning.getOffset());

            holder.createErrorAnnotation(element, warning.getText());
            LOGGER.info("Apply");
        });
    }
}

package com.jokerzoid.intellij.plugin.stylelint;

import com.intellij.lang.annotation.AnnotationHolder;
import com.intellij.lang.annotation.ExternalAnnotator;
import com.intellij.openapi.diagnostic.Logger;
import com.intellij.openapi.editor.Editor;
import com.intellij.psi.PsiElement;
import com.intellij.psi.PsiFile;
import com.intellij.psi.util.PsiUtil;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;

import java.util.List;

/**
 * @author Raul
 */
public class StylelintAnnotator extends ExternalAnnotator<PsiFile, List<StylelintWarning>> {
    private static final Logger LOGGER = Logger.getInstance(StylelintAnnotator.class);

    public StylelintAnnotator() {
        LOGGER.info("StylelintAnnotator");
    }

    @Nullable
    @Override
    public PsiFile collectInformation(@NotNull PsiFile file) {
        return file;
    }

    @Nullable
    @Override
    public PsiFile collectInformation(@NotNull PsiFile file, @NotNull Editor editor, boolean hasErrors) {
        return super.collectInformation(file, editor, hasErrors);
    }

    @Nullable
    @Override
    public List<StylelintWarning> doAnnotate(PsiFile file) {
        final StylelintOutput output = ProcessManager.runStylelint(file);

        return output.getWarnings();
    }

    @Override
    public void apply(@NotNull PsiFile file, List<StylelintWarning> warnings, @NotNull AnnotationHolder holder) {
        warnings.forEach(warning -> {
            final PsiElement element = PsiUtil.getElementAtOffset(file, warning.getOffset());

            holder.createWarningAnnotation(element, warning.getText());
            LOGGER.info("Apply");
        });
    }
}

Change Errors to Warnings