doc/payload: fix typo, minor formatting changes

doc/userguide/rules/payload-keywords.rst

@@ -293,7 +293,7 @@ It can take an argument "or_else" to match on absent buffer or on what comes nex
 
    alert http any any -> any any (msg:"HTTP request without referer";  :example-rule-emphasis:`http.referer; absent: or_else;` content: !"abc"; sid:1; rev:1;)
 
-For files (ie ``file.data``), absent means there are no files in the transaction.
+For files (i.e ``file.data``), absent means there are no files in the transaction.
 
 bsize
 -----
@@ -676,7 +676,7 @@ entropy
 
 The ``entropy`` keyword calculates the Shannon entropy value for content and compares it with
 an entropy value. When there is a match, rule processing will continue. Entropy values
-are between 0.0 and 8.0, inclusive. Internally, entropy is representing as a 64-bit
+are between 0.0 and 8.0, inclusive. Internally, entropy is represented as a 64-bit
 floating point value.
 
 The ``entropy`` keyword syntax is the keyword entropy followed by options
@@ -760,7 +760,7 @@ Example of the rpc keyword in a rule:
 replace
 -------
 
-The replace content modifier can only be used in ips. It adjusts
+The replace content modifier can only be used in IPS. It adjusts
 network traffic.  It changes the content it follows ('abc') into
 another ('def'), see example: