Fixes typos in sndsqr.md (#135)

* Fixes typos in sndsqr.md

Fixes a few typos and rewrites a couple things for readability.

I tried to be as little subjective as possible when it came to style, but feel free to discard or tweak changes if needed.

* Updates sndsqr.md

(another tiny paraphrasing tweak)

Author: SUPERNOOB20

content/sndsqr.md

@@ -242,7 +242,7 @@ While the full range between 20 Hz and 20 kHz is audible, only a discrete set of
 
 ### Fourier transforms and the square wave {#ssec-fourier}
 
-Fourier transformations are a way of going describing a function in the time domain as a distribution of frequencies called a <dfn>spectrum</dfn>. They're also one of the many ways that professors can scare the bejebus out of young, natural-science students. Don't worry, I'm sure you'll get through this section unscathed <kbd>\>:)</kbd>. For well- to reasonably-behaved functions, you can rewrite them as series of *very* well-behaved functions such as polynomials, exponentials and also waves. For example, as a Fourier series, a function may look like {@eq:fser}.
+Fourier transformations are a way of describing a function in the time domain as a distribution of frequencies called a <dfn>spectrum</dfn>. They're also one of the many ways that professors can scare the bejebus out of young, natural-science students. Don't worry, I'm sure you'll get through this section unscathed <kbd>\>:)</kbd>. For well - to reasonably - behaved functions, you can rewrite them as series of *very* well-behaved functions such as polynomials, exponentials and also waves. For example, as a Fourier series, a function may look like {@eq:fser}.
 
 <!--
 f(x) = \frac{1}{2}A_0 + \sum_{n>0}A_m\cos(m{\omega}t) + \sum_{n>0}B_m\sin(m{\omega}t)
@@ -1636,11 +1636,11 @@ const u32 __snd_rates[12]=
 
 Here you have a couple of constants for the note-indices, the LUT with rate-offsets `__snd_rates` and a simple macro that gives you what you want. While `__snd_rates` is constant here, you may consider a non-const version to allow tuning. Not that a square wave is anything worth tuning, but I'm just saying … y'know.
 
-One possible annoyance is that you have to splice the note into a note and octave part and to do that dynamically you'd need division and modulo by 12. Or do you? If you knew a few things about [division by a constant is multiplication by its reciprocal](fixed.html#sec-rmdiv), you'd know what to do. (<span class="small">Hint: *c*=(*N*\*43\>\>9)−2, with *N* the total note index between 0 and 95 (octave −2 to +5).</span>)
+One possible annoyance is that you have to splice the note into a note and octave part and to do that dynamically you'd need division and modulo by 12. Or do you? If you knew a few things about [division by a constant is multiplication by its reciprocal](fixed.html#sec-rmdiv), you'd know what to do. (<span class="small">Hint: *c*=(*N*\*43\>\>9)−2, where *N* is the total note index between 0 and 95 (octave −2 to +5).</span>)
 
 ## Demo time {#sec-demo}
 
-I think I've done about enough theory for today, don't you dear reader?
+I think I've done about enough theory for today; don't you, dear reader?
 
 “ \@\_@ ”
 
@@ -1762,7 +1762,7 @@ int main()
 
 The bolded code in `main()` initializes the sound register; nothing fancy, but it has to be done before you hear anything at all. It is important to start with `REG_SNDSTAT` bit 7 (`SSTAT_ENABLE`), i.e., the master sound enable. Without it, you cannot even access the other registers. Setting volume to something non-zero is a good idea too, of course. Then we turn off the sweep function and set sound 1 to use a fading envelope with a 50% duty. And that's where the fun starts.
 
-I'll explain what `sos()` in a little while, first something about the controls of the demo. You can play notes with the D-pad and A (hmm, there's something familiar about that arrangement). The octave *c* you're working in can be changed with L and R; the background color changes with it. B plays `sos()` again.
+I'll explain what `sos()` is in a little while; but first, something about the controls of the demo. You can play notes with the D-pad and A (hmm, there's something familiar about that arrangement). The octave *c* you're working in can be changed with L and R; the background color changes with it. B plays `sos()` again.
 
 <div class="lblock">
   <table>
@@ -1807,4 +1807,4 @@ There are two arrays here, `notes` and `lens`, and a loop over all elements. We
 
 The point I'm trying to make is that it's very well possible to play a tune with just the tone generators. Technically you don't need digitized music and all that stuff to play something. Of course, it'll sound better if you do, but if you just need a little jingle the tone generators may be all you need. Twelve years of Game Boy games using only tone generators prove this. Just define some notes (the nybble format for octaves and notes will do) and some lengths and you have the basics already. You could even use more than one channel for different effects.
 
-If you understood that, then get this: the note+length+channel idea is pretty much what tracked music (mod, it, xm, etc) does, only they use a more sophisticated wave than a square wave. But the principle is the same. Getting it to work takes a little more effort, but that's what Deku's [sound mix tutorial](https://stuij.github.io/deku-sound-tutorial/) is for.
+If you understood that, then get this: the note+length+channel idea is pretty much what tracked music (mod, it, xm, etc) does, only that they use a more sophisticated wave than a square wave. But the principle is the same. Getting it to work takes a little more effort, but that's what Deku's [sound mix tutorial](https://stuij.github.io/deku-sound-tutorial/) is for.