--request-target: instead of --strip-path-slash

... and CURLOPT_REQUEST_TARGET instead of CURLOPT_STRIP_PATH_SLASH.

This option instead provides the full "alternative" target to use in the
request, instead of extracting the path from the URL.

Test 1298 and 1299 updated accordingly.

Idea-by: Evert Pot
Suggestion: https://daniel.haxx.se/blog/2017/06/19/options-with-curl/comment-page-1/#comment-18373

Closes #1593

docs/cmdline-opts/Makefile.inc

@@ -42,6 +42,6 @@ DPAGES = abstract-unix-socket.d anyauth.d append.d basic.d cacert.d capath.d cer
   tlsauthtype.d tlspassword.d tlsuser.d tlsv1.0.d tlsv1.1.d tlsv1.2.d   \
   tlsv1.3.d tlsv1.d trace-ascii.d trace.d trace-time.d tr-encoding.d    \
   unix-socket.d upload-file.d url.d use-ascii.d user-agent.d user.d     \
-  verbose.d version.d write-out.d xattr.d strip-path-slash.d
+  verbose.d version.d write-out.d xattr.d request-target.d
 
 OTHERPAGES = page-footer page-header

docs/cmdline-opts/request-target.d

@@ -0,0 +1,8 @@
+Long: request-target
+Help: Specify the target for this request
+Protocols: HTTP
+---
+Tells curl to use an alternative "target" (path) instead of using the path as
+provided in the URL. Particularly useful when wanting to issue HTTP requests
+without leading slash or other data that doesn't follow the regular URL
+pattern, like "OPTIONS *".

docs/cmdline-opts/strip-path-slash.d

@@ -1,7 +0,0 @@
-Long: strip-path-slash
-Help: Strip off the first slash of the path
-Protocols: HTTP
----
-Tells curl to strip the leading slash from the path when it sends the path to
-the server. Useful when wanting to issue HTTP requests without leading slash,
-like "OPTIONS *".