Update 'Coding Standards' for 1.9+

[MattyWjeisz]

Reference: https://github.com/mybb/docs.mybb.com/blob/gh-pages/1.6/Coding-Standards.html

Remove HTML Markup

Remove any instance of markup in language files and move markup to templates.

$l['ignore_timezone'] = "<strong>Ignore time zone:</strong>"

$l['ignore_timezone'] = "Ignore time zone"

Remove Colon

Remove instances of ':' at the end of text. Semantically, this is unnecessary.

• The colon is often seen as unnecessary visual clutter, especially when the input field (like a checkbox or text box) immediately follows the label.
• Many contemporary web forms and applications omit the colon, relying on the spatial arrangement to signify the label-input relationship.
• Screen readers often announce the colon, which can add a slight, unnecessary pause or verbal cue for the user. Removing it can lead to a smoother auditory experience.
• Option text often functions as a mini-heading or label, and headings typically don't end with a colon.

Introduce Capitalisation

Capitalise labels.

$l['ignore_timezone'] = "Ignore time zone"

$l['ignore_timezone'] = "Ignore Time Zone"

[Sama34]

We can probably inherit some guidelines from well known sources :
https://m3.material.io/foundations/content-design/style-guide/grammar-and-punctuation

[Sama34]

• Identical comparison over Equal comparison
• Cast variables when expecting an exact type

if((int)$mybb->user['uid'] === 1) {
	///...
}