proc.5: Formatting fixes for /proc/PID/maps

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

man5/proc.5

@@ -349,8 +349,12 @@ bffff000-c0000000 rwxp 00000000 00:00 0
 .ft
 .fi
 
-where "address" is the address space in the process that it occupies,
-"perms" is a set of permissions:
+The 
+.I address
+field is the address space in the process that the mapping occupies.
+The
+.I perms
+field is a set of permissions:
 
 .nf
 .in +5
@@ -362,14 +366,24 @@ p = private (copy on write)
 .fi
 .in
 
-"offset" is the offset into the file/whatever, "dev" is the device
-(major:minor), and "inode" is the inode on that device.
+The
+.I offset
+is the offset into the file/whatever;
+.I dev
+is the device
+(major:minor), and
+.I inode
+is the inode on that device.
 0 indicates that no inode is associated with the memory region,
 as the case would be with BSS (uninitialized data).
 
-"pathname" will usually be the file that is backing the mapping.
+The
+.I pathname
+field will usually be the file that is backing the mapping.
 For ELF files,
-you can easily coordinate with the "offset" field by looking at the
+you can easily coordinate with the
+.I offset
+field by looking at the
 Offset field in the ELF program headers
 .RI ( "readelf\ \-l" ).
 
@@ -379,12 +393,12 @@ There are additional helpful pseudo-paths:
 .IR [stack]
 The initial process's (also known as the main thread's) stack
 .TP
-.IR [stack:<num>] " (since Linux 3.4)"
+.IR [stack:<tid>] " (since Linux 3.4)"
 A thread's stack (where the
-.IR <num>
+.IR <tid>
 is a thread ID).
 It corresponds to the
-.IR /proc/[pid]/task/[TID]/
+.IR /proc/[pid]/task/[tid]/
 path.
 .TP
 .IR [vdso]   
@@ -396,7 +410,9 @@ The process's heap.
 .fi
 .RE
 .IP
-If the "pathname" field is blank,
+If the
+.I pathname
+field is blank,
 this is an anonymous mapping as obtained via the
 .BR mmap (2)
 function.