Enable HAML-LINT linters

What does this MR do?

This MR enables new HAML Linters as mentioned in #22072 (closed) (particularly in this comment)

• AltText
• ClassAttributeWithStaticValue
• FinalNewline
• HtmlAttributes
• ImplicitDiv
• SpaceBeforeScript
• TrailingWhitespace
• SpaceInsideHashAttributes

Are there points in the code the reviewer needs to double check?

Pretty much every change needs to be reviewed as we want to be sure that an attempt to fix a Lint rule doesn't cause any unintended side-effect (which otherwise doesn't happen)

Why was this MR needed?

See #22072 (closed) and discussion thread in same issue.

Does this MR meet the acceptance criteria?

• Changelog entry added
• Documentation created/updated
• API support added
• Tests
  • Added for this feature/bug
  • All builds are passing
• Conform by the merge request performance guides
• Conform by the style guides
• Branch has no merge conflicts with master (if it does - rebase it please)
• Squashed related commits together

What are the relevant issue numbers?

Closes #22072 (closed)

app/views/notify/pipeline_failed_email.html.haml

@@ -90,7 +90,7 @@
                                       %tbody
                                         %tr
                                           %td{style: "font-family:'Helvetica Neue',Helvetica,Arial,sans-serif;font-size:15px;line-height:1.4;vertical-align:middle;padding-right:5px;"}
-                                            %img{height: "13", src: image_url('mailers/ci_pipeline_notif_v1/icon-branch-gray.gif'), style: "display:block;", width: "13"}/
+                                            %img{height: "13", src: image_url('mailers/ci_pipeline_notif_v1/icon-branch-gray.gif'), style: "display:block;", width: "13", alt: "Branch icon"}/
                                           %td{style: "font-family:'Helvetica Neue',Helvetica,Arial,sans-serif;font-size:15px;line-height:1.4;vertical-align:middle;"}
                                             %a.muted{href: commits_url(@pipeline), style: "color:#333333;text-decoration:none;"}
                                               = @pipeline.ref
@@ -101,7 +101,7 @@
                                       %tbody
                                         %tr
                                           %td{style: "font-family:'Helvetica Neue',Helvetica,Arial,sans-serif;font-size:15px;line-height:1.4;vertical-align:middle;padding-right:5px;"}
-                                            %img{height: "13", src: image_url('mailers/ci_pipeline_notif_v1/icon-commit-gray.gif'), style: "display:block;", width: "13"}/
+                                            %img{height: "13", src: image_url('mailers/ci_pipeline_notif_v1/icon-commit-gray.gif'), style: "display:block;", width: "13", alt: "Commit icon"}/
                                           %td{style: "font-family:'Helvetica Neue',Helvetica,Arial,sans-serif;font-size:15px;line-height:1.4;vertical-align:middle;"}
                                             %a{href: commit_url(@pipeline), style: "color:#3777b0;text-decoration:none;"}
                                               = @pipeline.short_sha
@@ -119,7 +119,7 @@
                                         %tr
                                           - commit = @pipeline.commit
                                           %td{style: "font-family:'Helvetica Neue',Helvetica,Arial,sans-serif;font-size:15px;line-height:1.4;vertical-align:middle;padding-right:5px;"}
-                                            %img.avatar{height: "24", src: avatar_icon(commit.author || commit.author_email, 24), style: "display:block;border-radius:12px;margin:-2px 0;", width: "24"}/
+                                            %img.avatar{height: "24", src: avatar_icon(commit.author || commit.author_email, 24), style: "display:block;border-radius:12px;margin:-2px 0;", width: "24", alt: "Avatar"}/
                                           %td{style: "font-family:'Helvetica Neue',Helvetica,Arial,sans-serif;font-size:15px;line-height:1.4;vertical-align:middle;"}
                                             - if commit.author
                                               %a.muted{href: user_url(commit.author), style: "color:#333333;text-decoration:none;"}