[css-layout-api] Fix a few minor typos in the spec and the explainer document

Author: mrego

css-layout-api/EXPLAINER.md

@@ -230,7 +230,7 @@ In step (3) we do some additional book-keeping to keep track of the largest chil
 
 ### Step (4) - Resolving the Block Size ###
 
-The now that we know how large our biggest child is going to be, we can calculate our actual
+Now that we know how large our biggest child is going to be, we can calculate our actual
 `blockSize`.
 
 We perform a call to `resolveBlockSize` again, except this time we also pass in the size that we
@@ -330,7 +330,7 @@ In the above example the text child produces two fragments. Containing:
 2. `the lazy dog.`
 
 The critical detail here to be aware of is the concept of a `BreakToken`. The `BreakToken` contains
-all of the information necessary to continue/resume the layout where we the child finished.
+all of the information necessary to continue/resume the layout where the child finished.
 
 We pass the `BreakToken` to add back into the `layout()` call in order to produce the next fragment.
 

css-layout-api/Overview.bs

@@ -88,7 +88,7 @@ Note: In a future level of the specification there may be a way to override the
 The 'overflow' property applies to <a>layout API containers</a>. This is discussed (TODO: writing
 about scrollbars).
 
-As the layout is entirely up to the author properties which are used in other layout modes (e.g.
+As the layout is entirely up to the author, properties which are used in other layout modes (e.g.
 flex, block) may not apply. For example an author may not call respect the 'width' or 'height'
 properties.