Fix early wrapping of the command line when using git-prompt.sh

When running git-prompt in Bash, the lack of \001 and \002 causes
the command line to wrap early.

The issue is the current \001 and \002 were not themselves escaped
and so resulted in binary 0b1 and 0b10 being present, rather than
the strings "\001" and "\002".

Signed-off-by: Richard Quadling <RQuadling@GMail.com>

Author: rquadling

contrib/completion/git-prompt.sh

@@ -147,7 +147,7 @@ printf -v __git_printf_supports_v -- '%s' yes >/dev/null 2>&1
 
 # like __git_SOH=$'\001' etc but works also in shells without $'...'
 eval "$(printf '
-	__git_SOH="\001" __git_STX="\002" __git_ESC="\033"
+	__git_SOH="\\001" __git_STX="\\002" __git_ESC="\033"
 	__git_LF="\n" __git_CRLF="\r\n"
 ')"
 

t/t9903-bash-prompt.sh

@@ -13,10 +13,10 @@ export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
 . "$GIT_BUILD_DIR/contrib/completion/git-prompt.sh"
 
 actual="$TRASH_DIRECTORY/actual"
-c_red='\001\e[31m\002'
-c_green='\001\e[32m\002'
-c_lblue='\001\e[1;34m\002'
-c_clear='\001\e[0m\002'
+c_red='\\001\e[31m\\002'
+c_green='\\001\e[32m\\002'
+c_lblue='\\001\e[1;34m\\002'
+c_clear='\\001\e[0m\\002'
 
 test_expect_success 'setup for prompt tests' '
 	git init otherrepo &&