FAQ: revise a bit

- use h3 for questions, h2 was rendering too large
- shorten some of the questions
- surround all cli flags with ``
- add some missing periods

FAQ.md

@@ -2,21 +2,21 @@ Frequently Asked Questions about scrot
 ======================================
 
 
-## Can I change the start of the selection area? ##
+### Can I change the start of the selection area?
 
 Yes. Using the arrow keys on your keyboard.
 
-## When I use the `--select` and `--pointer` options, how can I capture the mouse cursor if the cursor is being used for selection? ##
+### When I use `--select` and `--pointer`, how can I capture the cursor if it's being used for selection?
 
 Use the `--delay` option which will give you time to move the cursor
 into the selection area you have created.
 
-## How to avoid canceling the selection when pressing any key on the keyboard? ##
+### How to avoid canceling the selection when pressing any key on the keyboard?
 
 Use the `--ignorekeyboard` option. This option prevents exit by
-ignoring any keyboard event, except the ESC key.
+ignoring any keyboard event, except the <kbd>ESC</kbd> key.
 
-## The --select option leaves rectangle trails of the selection rectangle. How do I avoid this? ##
+### The `--select` option leaves rectangle trails of the selection rectangle. How do I avoid this?
 
 There are 2 ways to solve this:
 
@@ -27,7 +27,7 @@ Or using another selection mode: `scrot --select --line mode=edge`
 But this last one does not behave correctly with some
 CWM (Composite Window Manager)
 
-## Does scrot have a class name? ##
+### Does scrot have a class name?
 
 Yes. The class name is "scrot" and is useful only when using the
 `--line mode=edge`.
@@ -40,7 +40,7 @@ shadow-exclude = [
 ];
 ```
 
-## Why isn't the --freeze option enabled by default? ##
+### Why isn't the `--freeze` option enabled by default?
 
 The `--freeze` option generates a call to `XGrabServer` and, according to
 the X11 documentation, says the following:
@@ -59,16 +59,16 @@ purpose of the option, but rather to provide another alternative to
 the `--select` option to solve other problems.
 
 
-## What image file formats can I save my screenshot? ##
+### What image file formats can I save my screenshot?
 
 All formats supported by the Imlib2 library (present and future).
 
-## What is the image format that is saved by default? ##
+### What is the image format that is saved by default?
 
 The default format is PNG, even if it does not have a .png file
 extension.
 
-## Does it support redirection of the screenshot to the standard output? ##
+### Does it support redirection of the screenshot to the standard output?
 
 Yes. For example:
 
@@ -78,39 +78,39 @@ $ scrot -> myfile.png
 $ scrot - | pngquant -> myfile.png
 ```
 
-## Is there a default image format in the redirection to the standard output? ##
+### Is there a default image format in the redirection to the standard output?
 
 Yes. The default format is PNG. Use `--format` flag to change it.
 
-## What is the default line mode for the `--select` option? ##
+### What is the default line mode for the `--select` option?
 
-The default line mode is `--line mode=auto`
+The default line mode is `--line mode=auto`.
 
-## Do all sub-options of the `--line` option work for both line modes (edge, classic)? ##
+### Do all sub-options of the `--line` option work for both line modes (edge, classic)?
 
 No. For example the opacity sub-option is only for the edge line mode.
 To know more consult the man page.
 
-## When I use the `--select` option and click on the area of a window that is below another, this window does not rise, how can I solve this? ##
+### When I use the `--select` option and click on the area of a window that is below another, this window does not rise, how can I solve this?
 
 The way to force a window to have focus and rise is to add the
 `--border` option. However, this does not work on all WMs. So you may
 have to manually raise the window beforehand.
 
-## How do I change the opacity of the option `--select=hole` or `--select=hide?` ##
+### How do I change the opacity of the option `--select=hole` or `--select=hide?`
 
-Using `--line opacity=35`
+Using `--line opacity=35`.
 
-## How do I change the color of the option `--select=hole` or `--select=hide?` ##
+### How do I change the color of the option `--select=hole` or `--select=hide?`
 
-Using `--line color='Forest Green'`
+Using `--line color='Forest Green'`.
 
-## I am using an image (instead of just color) to hide a selection area with: `--select=hide,stamp.png`, can I change the opacity of this image? ##
+### I am using an image to hide a selection area with: `--select=hide,stamp.png`, can I change the opacity of this image?
 
-Yes. Using the opacity sub-option of the --line option:
-`--line opacity=35`
+Yes. Using the opacity sub-option of the `--line` option:
+`--line opacity=35`.
 
-## I am using an image to hide a selection area with: `--select=hide,stamp.png --line opacity=35`, but the image is always opaque, how do I fix this? ##
+### I am using an image to hide a selection area with: `--select=hide,stamp.png --line opacity=35`, but the image is always opaque, how do I fix this?
 
 The image you are using must have an alpha channel (RGBA).
 You will find out if you do the following:
@@ -119,15 +119,10 @@ You will find out if you do the following:
 $ file stamp.png
 ```
 
-Shows the following "8-bit/color RGBA", it has alpha channel.
+If it shows "8-bit/color RGBA", it has alpha channel.
+If it shows "8-bit colormap", it does not have alpha channel.
 
-```console
-$ file stamp.png
-```
-
-Shows the following "8-bit colormap", does not have alpha channel.
-
-## Why can't I use floating point numbers anymore? ##
+### Why can't I use floating point numbers anymore?
 
 Until version v1.7 it would silently convert a floating point number
 to a 0 (zero). Which is an error since it allowed the user to believe