[Rule]:Create consistent capitals rule

[JC-DSIT]

Is this

• a suggestion for a new rule
• an update to an existing rule
• a suggestion to remove a rule

Why is this change important

#9

The style guide is pretty clear on capitalisation:

Capitalisation
DO NOT USE BLOCK CAPITALS FOR LARGE AMOUNTS OF TEXT AS IT’S QUITE HARD TO READ.

Always use sentence case, even in page titles and service names. The exceptions to this are proper nouns, including:

departments (specific government departments - see below)
the Civil Service, with lower case for ‘the’
specific job titles
titles like Mr, Mrs, Dr, the Duke of Cambridge (the duke at second mention); Pope Francis, but the pope
Rt Hon (no full stops)
buildings
place names
brand names
faculties, departments, institutes and schools
names of groups, directorates and organisations: Knowledge and Innovation Group
Parliament, the House
titles of specific acts or bills: Housing Reform Bill (but use ‘the act’ or ‘the bill’ after the first time you use the full act or bill title)
names of specific, named government schemes known to people outside government: Right to Buy, King’s Awards for Enterprise
specific select committees: Public Administration Select Committee
header cells in tables: Annual profits
titles of books (and within single quotes), for example, ‘The Study Skills Handbook’
World War 1 and World War 2 (note caps and numbers)
Do not capitalise:

government - see government
minister, never Minister, unless part of a specific job title, like Minister for the Cabinet Office
department or ministry - never Department or Ministry, unless referring to a specific one: Ministry of Justice, for example
white paper, green paper, command paper, House of Commons paper
budget, autumn statement, spring statement, unless referring to and using the full name of a specific statement - for example, “2016 Budget”
sections or schedules within specific named acts, regulations or orders
director general (no hyphen), deputy director, director, unless in a specific job title
group and directorate, unless referring to a specific group or directorate: the Commercial Directorate, for example
departmental board, executive board, the board
policy themes like sustainable communities, promoting economic growth, local enterprise zones
general mention of select committees (but do cap specific ones - see above)
the military
Capitals for government departments
Use the following conventions for government departments. A department using an ampersand in its logo image is fine but use ‘and’ when writing in full text.

Attorney General’s Office (AGO)
Cabinet Office (CO)
Department for Business and Trade (DBT)
Department for Culture, Media and Sport (DCMS)
Department for Education (DfE)
Department for Energy Security and Net Zero (DESNZ)
Department for Environment, Food and Rural Affairs (Defra)
Department for Science, Innovation and Technology (DSIT)
Department for Transport (DfT)
Department for Work and Pensions (DWP)
Department of Health and Social Care (DHSC)
Foreign, Commonwealth and Development Office (FCDO)
HM Treasury (HMT)
Home Office (HO)
Ministry of Defence (MOD)
Ministry of Housing, Communities and Local Government (MHCLG)
Ministry of Justice (MOJ)

Captials are used in code blocks, code placeholders and acronyms. The linter should also account for this

Examples of new behaviour as a result of the change

For example:

Scenario: Someone has created a page with a lot of new content, some of the words are over complicated
Given a page exists
And the page contains words from the words to avoid list
When the linter runs against the page with the "words to avoid" rule
Then the linter should fail

Add as many scenarios as you can think of to define the full behaviour of the rule. You can see existing examples in features/style_guide/*.feature