Fix remaining docs issues: grammar, typos, broken content, and RST artifacts

[dereuromark]

Summary

Fixes remaining issues found during a thorough review of the English documentation.

Broken/corrupted content (2 files):

• development/rest.md — Fix broken sentence fragment (. is dangling after link) and incomplete sentence (missing verb "works")
• contributing/documentation.md — Fix wrong path cs/en/ → docs/en/, fix corrupted code-group block

RST conversion artifacts (3 files):

• core-libraries/text.md — Fix escaped \$phrase, \<span\> in blockquote → inline code
• core-libraries/email.md — Fix escaped \$mailer-\> in blockquote → inline code
• core-libraries/registry-objects.md — Fix escaped add\<registry-object\>() → inline code

Grammar errors (8 files):

• contributing/code.md — is a breaks → breaks, then next → the next
• controllers/middleware.md — encrypted with via → encrypted via
• plugins.md — Plugin should → Plugins should, container service → services
• views/helpers/breadcrumbs.md — as a the title → as the title, will applied → will be applied
• development/sessions.md — a apc → an apc
• orm/schema-system.md — a auto-increment → an auto-increment

Typos (4 files):

• appendices/5-2-migration-guide.md — stopPropogation → stopPropagation
• appendices/5-3-migration-guide.md — has now a additional → now has an additional
• views.md — $differenVar → $differentVar
• console-commands.md — webbrowser → web browser

Wrong path:

• plugins.md — tempaltes → templates

Code syntax in examples (2 files):

• controllers/components.md — Missing closing ) in delete(), missing ; in beforeFilter()
• core-libraries/email.md — Missing ; after getData()