The correct rule for punctuation within Quotation Marks, says:
Periods and commas always go inside quotation marks.
Example: He told us, "Put the period in the right place."
No! Not always.
The goal of a technical manual is to tell the user precisely what to do and how to do it. Sometimes, grammar gets in the way.
Consider the following sentence:
Type your name into the from field like this: "Doug." Then press the tab key.
This is misleading in a technical manual.
Quotation marks are often used in technical document to show exactly what the user should type into an input field. In these cases, the quotations show what a user should type verbatim.
Should they type the period? NO! not in this case. So the period does not belong inside the quotes. Instead, break the grammatical rule and write this:
Type your name into the from field like this: "Doug". Then press the tab key.
Now is is clear to the user that they should type Doug in the from filed, without the period.
You can try to avoid these grammatical problems by changing the sentence structure, but this may lead to other problems. For example, you may change the need for a period into the need for a comma. Or you may end up with a longer, more convoluted sentence, hardly clear, concise and a quick read.
Follow the correct rules for punctuation where ever possible, but keep clarity and technical correctness (rather than grammatical correctness) as the priority.
Make sure information is easy to find and can be clearly understood, even at the expense of making a few minor grammatical faux pas.