Fix minor issues in the English docs

[OneVth]

Fixes a few minor issues I came across in the English docs while working on the Korean translation (#6). Each is in its own commit.

Changes

• Typos — font-inteface-content → font-interface-content (combined-styling/page-25), and Content wil show → Content will show (title-styling/page-1).
• Broken code fence — in list-styling/_index.md the unordered-list example had ```md6- Never on one line, so the code block didn't render. Split it into the fence and the list items.
• Wrong heading anchor — heading-indicators/page-4.md linked to #enable-heading-indicators-globally-for-heading-3 on an H4 page; corrected to heading-4.
• Missing closing quote — readme/page-2.md had Type "Flexcyon in the search bar; added the closing quote ("Flexcyon").
• Wrong sample text — Table/_index.md had Sample table header in the Table Cell section (line 84); changed to Sample table cell to match the section. The Table header section (line 51) is unchanged.

hugo build passes clean.

Note: the Korean translation (#6) faithfully followed the pre-fix English source, so some of these (the typo, the broken fence, the wrong anchor) are present there too. Once this is merged I'll add a follow-up commit to #6 to bring it in line.

[bladeacer]

thanks for raising these :D

[bladeacer]

as mentioned in #6 , will be merging this to another branch so I can cherry pick to both master and staging. Will merge this after #6 is merged.