docs: fix typos and markup in ETag manpage sections

Reported-by: emanruse on github
Fixes #6273

docs/cmdline-opts/etag-compare.d

@@ -15,5 +15,5 @@ line with a desired ETag. An empty file is parsed as an empty ETag.
 Use the option --etag-save to first save the ETag from a response, and
 then use this option to compare using the saved ETag in a subsequent request.
 
-\fCOMPARISON\fP: There are 2 types of comparison or ETags, Weak and Strong.
+\fBCOMPARISON\fP: There are 2 types of comparison or ETags: Weak and Strong.
 This option expects, and uses a strong comparison.

docs/cmdline-opts/etag-save.d

@@ -10,8 +10,8 @@ usually part of headers returned by a request. When server sends an
 ETag, it must be enveloped by a double quote. This option extracts the
 ETag without the double quotes and saves it into the <file>.
 
-A server can send a week ETag which is prefixed by "W/". This identifier
+A server can send a weak ETag which is prefixed by "W/". This identifier
 is not considered, and only relevant ETag between quotation marks is parsed.
 
-It an ETag wasn't send by the server or it cannot be parsed, and empty
+It an ETag wasn't sent by the server or it cannot be parsed, an empty
 file is created.