[paulbalandan]

Description
Fixes RST markup errors that also render wrong in the current guide:

• guides/first-app/news_section.rst: removes a duplicated line fragment.
• installation/upgrade_sessions.rst and changelogs/v4.7.0.rst: removes stray backticks after inline literals, and names the method as paginate().
• installation/upgrade_450.rst: indents the second line of list item 2, so it renders as a list item again with its examples inside it.
• general/urls.rst: replaces a code span holding only a space with "Space character".
• general/common_functions.rst, libraries/email.rst and installation/upgrade_4xx.rst: replaces links to hard-coded Sphinx HTML anchors with :php:func: and :php:meth: roles, so Sphinx checks them.

Checklist:

• Securely signed commits
• Component(s) with PHPDoc blocks, only if necessary or adds value (without duplication)
• Unit testing, with >80% coverage
• User guide updated
• Conforms to style guide