docs(doc): remove resolved accessibility issues from statement

[DanielCouzens]

Removed the following resolved accessibility issues from the statement:

• 1.4.11 Non-text Contrast (Level AA) the perform query button has an insufficient contrast ratio between the button background and text.
• 1.4.12: Text Spacing (Level AA) Some H2 headings are too small by default, which could also impact the contrast ratio, leading to readability issues for some users who need adjusted text spacing.
• 2.4.2: Page Titles (Level A)
• A more descriptive title (and H1 tag) is needed to clarify the purpose of the SPARQL form page.

Relates to this ticket - https://github.com/epimorphics/hmlr-linked-data/issues/162

[bogdanadrianmarc]

LGTM!