PSRL: Changed method names for consistency and introduced backwards compatible methods (#7146)

* Documented new BackwardDeleteInput and changes to BackwardDeleteLine.

* Introduced BackwardKillInput that replicates BackwardKillLine before update.

* Introduced ForwardDeleteInput that replicates ForwardDeleteLine before update.

Co-authored-by: Maxime LABELLE <[email protected]>
Co-authored-by: Sean Wheeler <[email protected]>

Author: 3 people

reference/7.2/PSReadLine/About/about_PSReadLine.md

@@ -133,28 +133,42 @@ Delete the character before the cursor.
 - Vi insert mode: `<Backspace>`
 - Vi command mode: `<X>`, `<d,h>`
 
-### BackwardDeleteLine
+### BackwardDeleteInput
 
-Like BackwardKillLine - deletes text from the point to the start of the line,
+Like BackwardKillInput - deletes text from the point to the start of the input,
 but does not put the deleted text in the kill-ring.
 
 - Cmd: `<Ctrl+Home>`
 - Vi insert mode: `<Ctrl+u>`, `<Ctrl+Home>`
-- Vi command mode: `<Ctrl+u>`, `<Ctrl+Home>`, `<d,0>`
+- Vi command mode: `<Ctrl+u>`, `<Ctrl+Home>`
+
+### BackwardDeleteLine
+
+Like BackwardKillLine - deletes text from the point to the start of the line,
+but does not put the deleted text in the kill-ring.
+
+- Vi command mode: `<d,0>`
 
 ### BackwardDeleteWord
 
 Deletes the previous word.
 
 - Vi command mode: `<Ctrl+w>`, `<d,b>`
 
-### BackwardKillLine
+### BackwardKillInput
 
-Clear the input from the start of the input to the cursor. The cleared text is
+Clear the text from the start of the input to the cursor. The cleared text is
 placed in the kill-ring.
 
 - Emacs: `<Ctrl+u>`, `<Ctrl+x,Backspace>`
 
+### BackwardKillLine
+
+Clear the text from the start of the current logical line to the cursor. The cleared text is
+placed in the kill-ring.
+
+- Function is unbound.
+
 ### BackwardKillWord
 
 Clear the input from the start of the current word to the cursor. If the
@@ -271,15 +285,22 @@ Delete the next word.
 
 - Vi command mode: `<d,w>`
 
-### ForwardDeleteLine
+### ForwardDeleteInput
 
-Like ForwardKillLine - deletes text from the point to the end of the line, but
+Like KillLine - deletes text from the point to the end of the input, but
 does not put the deleted text in the kill-ring.
 
 - Cmd: `<Ctrl+End>`
 - Vi insert mode: `<Ctrl+End>`
 - Vi command mode: `<Ctrl+End>`
 
+### ForwardDeleteLine
+
+Deletes text from the point to the end of the current logical line, but
+does not put the deleted text in the kill-ring.
+
+- Function is unbound
+
 ### InsertLineAbove
 
 A new empty line is created above the current line regardless of where the