If a colon is required in the sentence in which the abbreviation occurs, there is no rule against a period preceding the colon.
A colon placed after the word including is not correct; this is because a colon should follow only independent clauses, which cannot end with that particular word. In other words, if you can correctly write a period in place of the colon, the colon's use is correct.
In typing, proper style is 2 spaces after a period (.), as well as after a colon (:).
I like how you don't give us the options: Ahole
I was taught it was two. A good way to remember this is by counting the dots on it. The colon has two so it has two spaces. A semi colon has only one dot, and it has only one space after it. But this only applies when the name of the punctuation has the word "colon" in it, as when you are counting the dots in a period, you only see one, but after a period, you usually put two spaces unless you are using a wesite address or something of that sort.
Master chefs agree that one characteristic is essential for all ingredients: freshness
A colon placed after the word including is not correct; this is because a colon should follow only independent clauses, which cannot end with that particular word. In other words, if you can correctly write a period in place of the colon, the colon's use is correct.
colon
The colon is a punctuation used for many purposes. It itself is a symbol, properly called a punctuation. This is a colon: simply a period with a period on top. This looks similar to the semi-colon, which looks like this ; a comma with a period on top.
In place of a period
A period or a colon.
A semi colon is a period with a comma just beneath it.
A semicolon is used to connect two closely related independent clauses without a conjunction. It can also be used to separate items in a list when the items contain commas.
Normally it would use a period. A colon is used where a number of values follows in a sentence, but may be used where there is a bulleted or itemized list (depends on style).
The sentence "I need to pack three things: clothes, shoes, and toiletries" is not an example of correct colon usage. Colons should only be used to introduce a list, a definition, or an explanation, but in this sentence, there is no need to introduce a list as it flows naturally without the colon.
In typing, proper style is 2 spaces after a period (.), as well as after a colon (:).
A semi-colon can be used to separate 2 sentences (2 complete thoughts), in place of a period.
Colon