Summary

Fix ~160 typos and grammar issues across 62 documentation files.

Categories of fixes:

• Duplicated words (~25): "the the", "to to", "between between", "integer integer", "will will", "in in", etc.
• Missing words/prepositions (~30): "depends the" → "depends on the", "helpful list" → "helpful to list", "refer the system" → "refer to the system", etc.
• Subject-verb agreement (~15): "builders outputs" → "builders output", "section describe" → "section describes", etc.
• British → American English (~12): "behaviour" → "behavior", "customise" → "customize", "internationalisation" → "internationalization", "programme" → "program", etc.
• Misspellings (~20): "mobile-optimated" → "mobile-optimized", "overriddent" → "overridden", "valuevgreater" → "value greater", "cross-refererence" → "cross-reference", "Pygment" → "Pygments", etc.
• Wrong articles (~10): "a extension" → "an extension", "an sub-entry" → "a sub-entry", "a iterable" → "an iterable", etc.
• Awkward phrasing (~15): "you can be done by using" → "this can be done by using", "how a doctest failure looks like" → "what a doctest failure looks like", etc.
• Other (~15): double spaces, extra periods, punctuation issues

Files affected: 62 documentation files across doc/, AUTHORS.rst, and CONTRIBUTING.rst.

No code changes. No CHANGES.rst entry needed per contributing guidelines (typo fixes).