DEAR MISS MANNERS: I friended an old classmate on social media. We weren’t close in school, but time passes, nostalgia sets in, and sometimes you like to reconnect. This girl was pleasant as a child, though not real bright, and a bit shy. Lately she’s been commenting on every one of my posts using alTerNaTinG cAps aNd lOweRcAsE letters. I’m a writer, editor and typographer, but I had to look this up to find out it’s meant to convey a mocking tone. I’m baffled by my friend’s use of this style because her comments themselves are either benign or complimentary. So the creepy, disjointed type styl…