DOC-3147: Fix lvl heading issues for TOC.

Author: kemister85

modules/ROOT/partials/a11y-rules/d3.adoc

@@ -1,5 +1,5 @@
 [[D3]]
-=== D3 - Adjacent links
+==== D3 - Adjacent links
 
 *Rule description:* this rule checks that links next to other links do not have the same `+href+` attribute.
 

modules/ROOT/partials/a11y-rules/d4o.adoc

@@ -1,5 +1,5 @@
 [[D4O]]
-=== D4O - Ordered list structure
+==== D4O - Ordered list structure
 
 *Rule description:* this rule checks that an `+ol+` element is used for ordered lists. Do not use paragraphs beginning with numbers or roman numerals instead of an `+ol+` element containing `+li+` items. This is to simplify navigation and parsing of the content for users of assistive technologies.
 

modules/ROOT/partials/a11y-rules/d4u.adoc

@@ -1,5 +1,5 @@
 [[D4U]]
-=== D4U - Unordered list structure
+==== D4U - Unordered list structure
 
 *Rule description:* this rule checks that a `+ul+` element is used for unordered lists. Do not use paragraphs beginning with `+*+` or `+-+` or some similar character instead of an `+ol+` element containing `+li+` items. This is to simplify navigation and parsing of the content for users of assistive technologies.
 

modules/ROOT/partials/a11y-rules/d5.adoc

@@ -1,5 +1,5 @@
 [[D5]]
-=== D5 - Contrast ratio of the text (D5A, D5B, and D5C)
+==== D5 - Contrast ratio of the text (D5A, D5B, and D5C)
 
 *Rule description:* this rule checks that the contrast ratio of the text is above the following values:
 

modules/ROOT/partials/a11y-rules/t4c.adoc

@@ -1,5 +1,5 @@
 [[T4C]]
-=== T4C - Table heading scope
+==== T4C - Table heading scope
 
 *Rule description:* this rule checks that all table header (`+th+`) elements have a `+scope+` attribute clarifying what scope the heading has inside of the `+table+`. The allowed values are `+row+`, `+col+`, `+rowgroup+`, and `+colgroup+`. This is important for users of assistive technologies to be able to parse table data.