Fix the casing on an image URL in the FTCS marks spec (#19440)

Author: pszlazak

.github/actions/spelling/expect/74d92373e136649071b3c04dc8773f18deaf5e04.txt

@@ -0,0 +1 @@
+ftcs

.github/actions/spelling/expect/expect.txt

@@ -540,7 +540,6 @@ EPres
 EQU
 ERASEBKGND
 ERRORONEXIT
-ESFCIB
 esrp
 ESV
 ETW
@@ -603,7 +602,6 @@ FONTSTRING
 FONTTYPE
 FONTWIDTH
 FONTWINDOW
-foob
 FORCEOFFFEEDBACK
 FORCEONFEEDBACK
 FRAMECHANGED
@@ -620,7 +618,6 @@ FUNCTIONCALL
 fuzzmain
 fuzzmap
 fuzzwrapper
-fuzzyfinder
 fwdecl
 fwe
 fwlink
@@ -961,7 +958,6 @@ lsb
 lsconfig
 lstatus
 lstrcmp
-lstrcmpi
 LTEXT
 lto
 ltsc
@@ -1125,7 +1121,6 @@ NOREPOSITION
 NORMALDISPLAY
 NOSCRATCH
 NOSEARCH
-noselect
 NOSELECTION
 NOSENDCHANGING
 NOSIZE
@@ -1183,7 +1178,6 @@ onecoreuuid
 ONECOREWINDOWS
 onehalf
 oneseq
-oob
 openbash
 opencode
 opencon

doc/specs/#11000 - Marks/Shell-Integration-Marks.md

@@ -111,7 +111,7 @@ not understanding these sequences originally.
 The relevant FinalTerm sequences for marking up the prompt are as follows.
 
 
-![image](FTCS-diagram.png)
+![image](ftcs-diagram.png)
 
 * **FTCS_PROMPT**: `OSC 133 ; A ST`
   - The start of a prompt. Internally, this sets a marker in the buffer