fix typos

exercises/106_tokenization.zig

@@ -14,7 +14,7 @@
 // exercises.
 //
 // A nice example of this has been published on the Zig homepage,
-// replacing the somewhat dusty 'Hello world!
+// replacing the somewhat dusty 'Hello world!'
 //
 // Nothing against 'Hello world!', but it just doesn't do justice
 // to the elegance of Zig and that's a pity, if someone takes a short,

exercises/112_vectors.zig

@@ -73,7 +73,7 @@
 // Operations performed on vectors in Zig will be done in parallel using
 // SIMD instructions, whenever possible.
 //
-// Defining vectors in Zig is straightforwards. No library import is needed.
+// Defining vectors in Zig is straightforward. No library import is needed.
 const v1 = @Vector(3, i32){ 1, 10, 100 };
 const v2 = @Vector(3, f32){ 2.0, 3.0, 5.0 };
 

exercises/114_packed.zig

@@ -1,9 +1,9 @@
 //
 // We've already learned plenty about bit manipulation using bitwise operations
-// in exercices 097 and 098 and in quiz 110. The techniques we already know work
+// in exercises 097 and 098 and in quiz 110. The techniques we already know work
 // just fine, but creating masks and shifting individual bits around can become
 // quite tedious and unwieldy pretty quickly.
-// What if there was a better, a more convenient way to control invidivual bits?
+// What if there was a better, a more convenient way to control individual bits?
 //
 // Luckily, Zig has a keyword for exactly this purpose:
 //